J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 113 http://jad.tums.ac.ir Published Online: January 05, 2016 Review Article Measures to Control Phlebotomus argentipes and Visceral Leishmaniasis in India DeAnna C. Bublitz 1, *Richard M. Poché 1, Rajesh Garlapati 2 1Genesis Laboratories, 10122 NE Frontage Road, Wellington, CO 80549, USA 2Genesis Laboratories India Private Limited, Patna, Bihar, India (Received 11 Apr 2015; accepted 26 Oct 2015) Abstract Visceral leishmaniasis is a deadly parasitic disease that is transmitted via the bite of a female sand fly, Phlebotomus argentipes. The highest burden of this disease is in northern India. In 2005, India embarked on an initiative with Ne- pal, Bangladesh, and the World Health Organization to eliminate visceral leishmaniasis by 2015. With the goal of 1 case in 10,000 people still unmet, it is prudent to evaluate the tools that have been used thus far to reduce vector numbers and cases of the disease. Herein, we present a review of studies conducted on vector-control strategies in India to combat visceral leishmaniasis including indoor residual spraying, insecticide-treated bed nets, environmental modification, and feed-through insecticides. This review suggests that the quality of indoor residual spraying may enhance control measures while a combination of spraying, nets, and feed-through insecticides would best confront the diverse habitats of P. argentipes. Keywords: Visceral leishmaniasis, Leishmania donovani, Phlebotomus argentipes, sand flies, vector control Introduction Leishmaniasis is a parasitic disease that can manifest in three forms: 1) mucosal, 2) cutaneous, and 3) visceral (WHO 2010, Maroli et al. 2013). Visceral leishmaniasis (VL) is the most severe form caused by the proto- zoan flagellate, Leishmania donovani (East Africa and Indian subcontinent) and L. in- fantum (also known as L. chagasi, found in Europe, North Africa, and Latin America). As this review focuses on elimination efforts in India, we will only refer to L. donovani in this article. Globally, the annual incidence rate is approximately 200,000–400,000 cases, the majority of cases are present in Bangla- desh, Nepal, and India. Furthermore, two- thirds of those cases occur in India where VL (also known as kala-azar; black fever) is endemic in the states of Uttar Pradesh, Jhar- khand, West Bengal, and Bihar (Alvar et al. 2006, Joshi et al. 2008, Alvar et al. 2012). Reports have noted the annual incidence in India as 146,700–282,800 cases with a mor- tality rate of at least 2.4%. However, other studies involving active searches at the vil- lage level have discovered mortality rates from 10–20%, partly due to a delay in di- agnosis (Alvar et al. 2012). VL carries a mortality rate over 90% when left untreated (Desjeux 1996, Jeronimo et al. 2006). Trans- mission of L. donovani occurs via the bite of a female Phlebotomus argentipes sand fly. Of the nearly 50 species of sand flies present in India, P. argentipes is the only one known to transmit VL in this country (Kumar et al. 2012). Once the parasite is in the human body it rapidly invades macrophages and eventually moves in this way to the liver, spleen, and lymph nodes (Chappuis et al. 2007). Symptoms include: fever lasting weeks to months, splenomegaly, hepatomegaly, and anemia (Desjeux 1996, Guerin et al. 2002, Chappuis et al. 2007). Of patients that recov- *Corresponding author: Dr Richard M. Poché, E- mail: richard@genesislabs.com J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 114 http://jad.tums.ac.ir Published Online: January 05, 2016 er, an estimated 5–10% go on to develop a rash known as post kala-azar dermal leish- maniasis (PKDL), this can occur anywhere from several months to several years follow- ing treatment (Ramesh and Mukharjee 1995, Rahman et al. 2010). PKDL patients do not experience other symptoms outside of the rash, however, they are thought to serve as a reservoir for L. donovani where feeding sand flies can acquire the parasite (Addy and Nandy 1992, Rahman et al. 2010). As hu- mans are the only known reservoir for L. do- novani in India, PKDL patients are another concern for VL elimination efforts. Visceral Leishmaniasis is a poverty-asso- ciated disease linked to poor housing and sanitary conditions and malnutrition, these factors have led to a number of difficulties regarding treatment and elimination (Cerf et al. 1987, Thakur 2000, Boelaert et al. 2009, Singh et al. 2010, Picado et al. 2014). Easy access to medical care in the rural VL-en- demic regions of India is still limited, mean- ing patients are not routinely identified or wait until the disease has progressed to more severe symptoms before seeking treatment. Moreover, until recently treatment regimens required medication injections over the course of 20–28 days leading to poor compliance rates (Clem 2010, Moore and Lockwood 2010, Stockdale and Newton 2013). In addi- tion to hurdles with medical treatment, in- creased sand fly density has been associated with certain types of housing, owning live- stock, and nearby vegetation (Ranjan et al 2005, Singh et al. 2010, Poché et al. 2011, Poché et al. 2012, Perry et al. 2013, Malavi- ya et al. 2014, Picado et al. 2014). The risk of exposure to P. argentipes is even higher for some, as many people in these poor re- gions of India live in close proximity to their cattle, keeping them inside their dwellings (Singh et al. 2010, Perry et al. 2013, Malavi- ya et al. 2014). As a by-product of DDT spraying for ma- laria elimination programs in the 1950s and 1970s, VL was nearly eliminated. However, when DDT spraying ended, sand fly num- bers and cases of VL rose again, leading to several major epidemics (Kishore et al. 2006, Thakur 2007, Ostyn et al. 2008). In 2005, the governments of Bangladesh, Ne- pal, and India began a concerted VL elimi- nation effort, with a target goal of 2015 for elimination (1 case in 10,000 people). Indoor residual spraying (IRS) and insecticide-treat- ed bed nets (ITN) have been the main forms of control regimens tried in India, while en- vironmental modification (EVM) and feed- through insecticides (FTI) have been less studied. Despite significant efforts to control sand flies and treat infected persons, the country remains a bastion for this disease. As such, we sought to review the current practices regarding vector/VL control pro- grams in India. A literature search was per- formed using the term “India” in combina- tion with the following keywords: Phleboto- mus argentipes, sand fly, kala-azar, and/or visceral leishmaniasis. The following paper is a summation of the articles collected in hopes of highlighting what has worked, what has not, and what can be learned as we move forward towards elimination goals. Control Strategies Indoor Residual Spraying IRS has been the main line of defense against vector-borne diseases in India. In the 1950s and again in the 1970s there were ag- gressive IRS initiatives to eliminate malaria (Kishore et al. 2006, Thakur 2007, Ostyn et al. 2008). During these years, households in malaria-endemic regions, many of which were the same as VL-endemic areas, were sprayed with DDT to cull mosquitoes. Sand fly populations declined in kind, and with them, cases of VL. However, at the end of those campaigns, with no systematic IRS programs, sand fly populations and cases of J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 115 http://jad.tums.ac.ir Published Online: January 05, 2016 VL quickly rebounded (Kishore et al. 2006, Thakur 2007, Ostyn et al. 2008). Since then, IRS using DDT has been em- ployed to fight VL transmission in India with mixed results. Currently, the National Vector Borne Disease Control Programme of India dictates that IRS should be performed on all homes and cattle sheds in endemic regions. They recommend two annual appli- cations, the first to occur in February/March and the second in May/June (NVBDCP 2014). Applied properly, IRS has been shown to dramatically impact P. argentipes density (Joshi et al. 2009). In that carefully con- trolled study involving all homes in six clus- ters in each of four villages, there was a 72.4% decline in sand fly numbers. Other studies that have assessed the efficacy of IRS in India have instead highlighted a number of issues limiting its success in con- trolling sand flies and VL. Huda et al. mon- itored local IRS programs for control of VL in Bangladesh, Nepal, and India (2011). In India, (though it was not unique for some of these issues) they found functional pumps and spare parts were lacking and 23.5% of the pumps were leaking. Spraying staff were not adequately trained and as such, proper mixing of DDT was done only 29.4% of the times observed. Additionally, proper distance and swath coverage during spraying were maintained only 49% and 58.8% of the time, respectively (Huda et al. 2011). These results are echoed in a similar report that found the same issues with equipment, training, mix- ing, and distance from surface, in addition to storage and quality issues for the DDT (Chowdhury et al. 2011a). This group also noted that the DDT residue levels on the walls varied at the village level from 66%– 90% of the intended concentration while at the household level, the concentration varied as much as 9.1% to 330% (Chowdhury et al. 2011a). Furthermore, spraying must be ap- plied to >80% of the homes in an area for mass effect (CDC 2012). According to Huda et al. the reported coverage rate in their study was only 64% (2011). Another point of concern with IRS in In- dia is resistance of P. argentipes to DDT. Resistance to DDT was documented for the district of Samastipur in Bihar, India as early as 1990 (Mukhopadhyay et al. 1992). In gen- eral, P. argentipes remains largely suscepti- ble to DDT with the majority of flies suc- cumbing to the insecticide (Singh et al. 2001, Dhiman et al. 2003, Joshi et al. 2009). How- ever, select districts are showing signs of this trend shifting (Kishore et al. 2004). Hu- da et al. documented only a 54% mortality rate after 24 h for sand flies exposed to walls sprayed with DDT while another group found up to 70% were killed when exposed to surfaces that had been sprayed 2 weeks prior (Chowdhury et al. 2011a). It is possible that the results obtained by Huda and Chow- dhury et al. may have been partly due to im- proper storage, mixing, spraying, and/or ac- tive ingredient concentration which were all problems documented by those studies (Chowdhury 2011a, Huda 2011a). A con- trolled study involving IRS in three states in India found mortality rates for P. argentipes ranging from 31–89%, indicating moderate to significant levels of resistance to DDT, even with proper use (Singh et al. 2012). Despite these many problems recorded by groups studying IRS, in all of the aforemen- tioned studies, post-treatment sand fly abun- dance was significantly reduced in the short term (Chowdhury et al. 2011a, Huda et al. 2011, Singh et al. 2012). In fact, Joshi et al. demonstrated a negative effect on sand fly numbers up to five months post-treatment (Joshi et al. 2009). Both Nepal and Bangla- desh employ pyrethroids for their IRS regi- mens and have shown them to be effective (Joshi et al. 2009, Chowdhury et al. 2011a, Chowdhury et al. 2011b). Some work has been conducted using different insecticides in India. In one report they found sand flies were resistant to DDT but not deltamethrin J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 116 http://jad.tums.ac.ir Published Online: January 05, 2016 (Dhiman et al. 2003). A more recent study documented that deltamethrin was effective in nearly 100% of the locations tested in In- dia (Singh et al. 2012). The government of India is currently testing the efficacy of syn- thetic pyrethroids on sand fly control in Bi- har (NVBDP 2014). A comprehensive table of susceptibility studies can be found in the review by Ostyn et al. (2008). While IRS can aid in controlling en- dophilic sand flies, it does not address out- door transmission of VL. In India, P. argen- tipes are peridomestic, found in cattle enclo- sures as well as vegetation (Poché et al. 2011, Perry et al. 2013, Poché et al. 2012). Another matter that is infrequently addressed in studies regarding IRS is the health effects to humans, animals, and the environment as a result of frequent and long-term IRS. The Stockholm Convention on persistent organic pollutants has banned DDT (van den Berg 2009). However, there is yet no consensus on whether DDT exposure leads to deleteri- ous health effects among humans (Sharpe and Stewart 2004, Beard 2006). Regardless, there are well documented studies regarding its toxicity in birds and a variety of aquatic species (Blus 2003, Sparling 2010, Beckvar and Lotufo 2011). While further work is needed to verify them, these data indicate that alternative IRS compounds may be more efficacious in controlling P. argentipes abundance. Research looking at effects on human health due to long-term exposure would still need to be addressed. Ultimately, these data suggest that with proper execu- tion, IRS could be an even more effective tool against VL in India but is not sufficient as a standalone given that P. argentipes is found outdoors in significant numbers. Bed Nets Bed nets, in particular, ITNs and long- lasting insecticide nets (LLINs), have been suggested as alternatives and/or comple- ments to IRS for the control of sand fly pop- ulations and VL. ITN/LLINs have been ef- fective against other vector-borne diseases, including cutaneous leishmaniasis (Lengeler 2004, Kulkarni et al. 2007, Wilson et al. 2014) but there are mixed results when it comes to sand flies in India. A trial using untreated nets found that the number of fe- male, blood-fed P. argentipes declined by 85% following the introduction of the nets (Picado et al. 2009). However, the authors of that study note that they lacked concurrent controls and thus, blood-feeding rates could potentially be attributed to changes in envi- ronmental factors (temperature, humidity, precipitation) or changes in host availability (i.e. an increase in domestic animals). Even so, other groups in Bangladesh and Nepal have found similar results (Bern et al. 2000 and 2005). Outside of that one study, all others have utilized ITNs or LLINs in India. The report by Joshi et al. investigated the usefulness of IRS, LLINs, and EVM to mitigate sand fly density in India, Nepal, and Bangladesh. When LLINs were in place, there was a vil- lage-wide reduction in P. argentipes num- bers by 43.7% in India when measured 5 months post-intervention (Joshi et al. 2009). A subsequent village-wide study in India noted a 25% decline in sand fly density (Pic- ado et al. 2010a). In that study, 16 clusters were enrolled, of those, 10 were used for sand fly capture studies. The reduction ap- peared to be at the community level and not displacement as P. argentipes abundance did not increase in cattle enclosures (Picado et al. 2010a). However, this observation does not exclude other environmental refuges, such as vegetation (Poché 2011, Poché 2012). As a part of the same study by Picado et al. they also investigated rates of VL in these same villages and found no protective effect of LLINs on the rate of seroconver- sion (Picado et al. 2010b). Nearly 20,000 people were enrolled in the seroconversion study. Over the course of 24 months, inci- J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 117 http://jad.tums.ac.ir Published Online: January 05, 2016 dence of L. donovani infection was found to be 5.4% in the intervention group and 5.5% in the control group while clinical VL rates were 0.38% and 0.40% in the intervention and control groups, respectively. One expla- nation for this result was that LLINs do not prevent outdoor transmission (Picado et al. 2010b). An earlier study of 48 homes and mixed dwellings (homes shared with livestock) in Bihar compared two types of LLINs to two types of untreated nets and looked at sand fly densities. At all time-points, up to 9 weeks post-treatment, there were no differ- ences in P. argentipes abundance between the groups (Dinesh et al. 2008). It should be noted, that during the course of the afore- mentioned studies, unplanned IRS took place, and in both cases there was no notice- able effect on the number of sand flies cap- tured in either study (Dinesh et al. 2008, Picado et al. 2010a). Furthermore, when the statistical models used to analyze the VL seroconversion data were adjusted for IRS, no changes were found (Picado et al. 2010b). While the number of studies has been limited, the efficacy of bed nets in India to combat VL have not shown the same prom- ise as they have in Bangladesh (Chowdhury et al. 2011b, Mondal et al. 2013). The po- tential reasons for this are many, including: study design, environmental factors (temper- ature, humidity, flooding etc.), and suscepti- bility to insecticides - P. argentipes in Bang- ladesh may be more susceptible, given their history of IRS campaigns is more recent compared to India (Bern et al. 2006, Picado et al. 2010a, Chodhury et al. 2011b). As breeding sites are yet unknown, and sand flies have been associated with vegetation in India, these remain confounding factors when accounting for differences in interven- tion strategies (Poché et al. 2011, Poché et al. 2012). Non-compliance and net quality are another concern. In the studies by Picado and Joshi, care was taken to inspect the nets and ensure compliance (Joshi et al. 2009, Picado et al. 2010a, 2010b). Even so, com- pliance with nets can be difficult as sand flies are much smaller than mosquitoes re- quiring finer mesh that people find stifling to sleep under in the heat of summer (Ostyn et al. 2008, Perry et al. 2013). While in theory, the impregnated insecticide should provide repellent activities, thus allowing for a larger mesh, efficacy in the field has not been shown (Picado et al. 2010a, 2010b). Moreover, 93% of 1,217 people surveyed in 2009–2011 in VL-endemic regions reported sleeping out- side at some point during the hottest months of the year (Perry et al. 2013). Assuming this trend holds true throughout other VL-af- flicted areas, this is a serious hurdle to be faced in regards to the efficacy of IRS, ITNs, and EVM as none mitigate transmission that occurs outside of a person’s dwelling. Environmental Modification Typical dwellings in the regions of India afflicted by VL are often made of mud and thatch, or brick/plaster. Some have earthen floors while others have brick or cement (Perry et al. 2013, Malaviya et al. 2014). In all cases, cracks and crevices where sand flies can rest and hide are prevalent. All home types are susceptible to habitation by P. argentipes, but thatched homes in partic- ular cater to high densities (Malaviya et al. 2014). EVM is a method little studied when compared to IRS and ITNs as a means to control VL in India. EVM has generally meant alterations to the home or surrounding environment by means of covering or filling in cracks and crevices in walls and floors. A pilot study involving 15 homes saw a reduction in sand fly numbers using a mud and lime plaster mix to seal cracks in homes and cattle enclosures (Kumar et al. 1995). The same well-controlled study comparing the efficacy of IRS and ITNs in India, Nepal, and Bangladesh found a 42% decline in sand fly abundance five months after the walls of J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 118 http://jad.tums.ac.ir Published Online: January 05, 2016 homes and cattle enclosures were plastered with a mud and lime mixture. The negative effect on sand fly populations may be due to the lime pH or limiting available moisture, thus, inhibiting breeding of P. argentipes, though breeding sites for these flies have not been confirmed (Kumar et al. 1995, Sharma and Singh 2008, Joshi et al. 2009). Indeed, a study in Bangladesh saw no effect on sand fly populations when crevices were filled with mud (Chowdhury et al. 2011b). Im- portantly, another study in India found mud- plastered walls themselves to be risk factor for VL (Ranjan et al. 2005). However, while mud/lime mixes are effective, this method requires continual maintenance and is costly compared to IRS and ITNs (Das et al. 2008). But like IRS and ITN, it is only effective against the sand flies that are inside homes; populations that reside in outdoor enclosures and vegetation would remain a source of VL. Feed-Through Insecticides A newer, relatively untested, yet promis- ing addition to the vector-control arsenal is the use of FTIs. Several compounds includ- ing ivermectin, fipronil, and imidacloprid have been tested in rodents to cull P. papa- tasi, a vector for cutaneous leishmaniasis (Mascari et al. 2008, Wasserberg et al. 2011, Mascari et al. 2013, Derbali et al. 2014). In these reports, the agents have been effective at controlling adult and larval sand flies when fed on blood or feces from treated an- imals, respectively. In regards to P. ar- gentipes, ivermectin and fipronil as well as diflubenzuron and eprinomectin were tested as FTIs in rats (Ingenloff et al. 2013). In that study, fipronil at 150 ppm was shown to re- sult in the quickest mortality and its effects had greater longevity than the other three compounds, even when they were used at greater concentrations. Fipronil has been the only FTI further evaluated for control of P. argentipes. Cattle and other livestock act as a major source of blood meals for female sand flies. Blood-meal analysis in one study found that 39.3% of the flies tested had fed on some form of livestock (Garlapati et al. 2012). So as to target P. argentipes that are feeding off of cattle and therefore, possibly residing outdoors, a controlled study involving cattle dosed with 0.5, 1.0, 2.0, and 4.0 mg/kg body weight of fipronil was conducted (Poché et al. 2013). That investigation demonstrated that fipronil as an FTI is effective, even at the lowest dose, at killing both adult and lar- val sand flies. The majority of adult sand flies had a 100% mortality rate within four days when fed on cattle up to 21 days post- treatment for all but the lowest dose (which had a ~22% mortality rate at 21 days post- treatment). Nearly all of the flies that were fed on days 1, 3, and 5 post-treatment suc- cumbed on the same day. For larval P. ar- gentipes, the mean-time to death when fed on feces from cattle 1 or 3 days post-treat- ment was 4.5 days, larva fed on feces with the lowest dose (0.5 mg/kg) on day 1 post- treatment had 100% mortality within 5.5 days while the highest dose (4.0 mg/kg) was 4.0 days. Additionally, for all doses tested, 100% mortality of larval sand flies was achieved by day 15.5 when fed on dung col- lected 21 days post-treatment (Poché et al. 2013). Given that this method is untested under field conditions, conclusions regarding its ef- fect on P. argentipes abundance or VL trans- mission cannot be drawn at this time. While no effects to cattle health were noted in the aforementioned study, future work will need to be done to assess the health of cattle treat- ed long-term. Moreover, at the lowest dose, fipronil can remain in the animal for up to 35 days but it is at concentration below interna- tional allowable limits (Poché et al. 2013). Regardless, future studies should also ad- dress milk consumption by humans from these cattle. Studies regarding the efficacy of fipronil as an FTI are ongoing and if they J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 119 http://jad.tums.ac.ir Published Online: January 05, 2016 prove positive, this method would be a val- ued addition to IRS and ITNs as it would better address exophilic P. argentipes, mak- ing control measures more comprehensive. Conclusion With humans as the only known reservoir for VL in India, rapid diagnosis and treat- ment would go a long way in controlling ep- idemics. However, if PKDL patients serve as a source of L. donovani, vector-control pro- grams will also be needed to reach the goal of elimination. In this way, surveillance and reporting programs may need to be reevalu- ated as under-reporting of VL remains an issue within India (Mubayi et al. 2010). Taking into account the diverse feeding and living habits of P. argentipes, it is likely that a combination of control measures will be necessary to eliminate VL in India. IRS, when executed properly can be highly effec- tive (Joshi et al. 2009). Switching insecti- cides may be beneficial with mounting evi- dence of increased resistance of P. argenti- pes to DDT coupled with potential health effects on humans, animals, and the envi- ronment (Blus 2003, van den Berg 2009, Sparling 2010, Huda et al. 2011, Singh et al. 2012, Cohn et al. 2015). In the end, the effi- cacy of IRS is dependent on organized gov- ernment programs that coordinate the spray- ing schedule and train the technicians, which can be either a benefit or hindrance depend- ing on the resources available to these groups (Joshi et al. 2009, Chowdhury et al. 2011a, Huda et al. 2011). Even still, IRS works well to curb adult P. argentipes abun- dance. Efforts should also be placed on iden- tifying breeding grounds. To this end, IRS could be focused and effective at eliminating both adult and larval flies. Insecticide treated nets have shown lim- ited success in India despite reports of their usefulness in other countries in combating sand fly densities (Dinesh et al. 2008, Picado et al. 2010a, 2010b). While there is some level of personal protection from sand flies afforded to people who use bed nets, more work would need to be done to confirm that the cost of these initiatives is validated. ITNs can often be more effective control measures against disease-transmitting vectors as prop- er use is in the hands of the affected persons instead of an outside program. That being said, non-compliance in India could be a problem as many people report sleeping out- doors during the hot summer months (Perry et al. 2013). Long-lasting insecticide nets can have repellent and insecticidal properties for years, making them a relatively cheap supplement to IRS, however, given the im- poverished state of most of the afflicted re- gions, nets may still need to be provided by government or non-profit groups. The most expensive of the three most studied intervention strategies is EVM (Das et al. 2008). A mud and lime mixture to seal cracks and crevices in walls and floors has shown some negative effects on sand fly abundance, yet these studies have been lim- ited (Kumar et al. 1995, Joshi et al. 2009). Given the cost and need for continual mainte- nance, EVM is a strategy that may be best left for use on a case-by-case basis rather than a district-wide, vector-control measure. The state of dwellings in VL-endemic vil- lages is a by-product of the greater issue of region-wide poverty, if that issue were better addressed, EVM would be a moot point. The last strategy covered in this report is FTI. This relatively new addition to VL vec- tor-control has been effective at killing both adult and larval P. argentipes under con- trolled settings (Inglenoff et al. 2013, Poché et al. 2013). At this time there is no known resistance by sand flies to fipronil and the tactic of dosing cattle begins to address out- door transmission of VL. However, FTIs would still rely on proper usage by in- dividuals and like ITNs, would carry similar benefits and risks of proper use. Similar to J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 120 http://jad.tums.ac.ir Published Online: January 05, 2016 IRS, FTIs will result in the potential for some human, animal, and environmental ex- posure. Although, reported residue levels of fipronil in milk is below international stand- ards (Poché et al. 2013), long-term studies have not been conducted. Work would need to be done to monitor for any adverse effects to humans, animals, and the environment, following long-term use of FTIs to treat cat- tle. Should FTIs prove effective under field conditions, they would begin to fill the gap in available treatments that target sand flies outside of homes and cattle enclosures. Similar to FTI and IRS is the use of natu- ral botanicals as insecticides in place of syn- thetic chemicals. One study demonstrated that a 2% concentration of neem oil mixed with either coconut or mustard oil was ef- fective at repelling sand flies from human subjects in India (Sharma and Dhiman 1993). While no work has been done re- garding the use of potential biochemicals as insecticides in India, studies conducted in other countries on different sand fly species showed that various plant-derived com- pounds were effective at killing adult and larval stages of the insects (Dinesh et al. 2014). Although many of the tested bio- chemicals only had a ~50% mortality rate, this area of research is still relatively unex- plored and may be a useful alternative to synthetic insecticides. With millions of homes that would re- quire intervention, vector-control programs need to balance rapid efficacy with long- term cost to ensure that if a treatment meas- ure is terminated the country does not expe- rience the rapid resurgence as occurred at the end of DDT IRS in the 1970s. One year of IRS costs on average, $5.90 per household which is more than LLINs ($4.50/house/ year) but less than EVM ($8.70/house/year), and those costs have likely only gone up since that report was conducted (Das et al. 2008). There is a real need for thorough cost- effectiveness studies using combinations of control measures and disease prevalence/ sand fly population scenarios. Research doc- umenting the direct and indirect costs, esti- mated expenditures for effective training and supervision of staff, as well as equipment maintenance would help to make informed decisions on the best use of resources for this endeavor. Moreover, modelling has been done to es- timate what percent of the sand fly popu- lation would need to be culled in order for VL to be eliminated. In that report, if sand fly life expectancy was reduced (eg via IRS, ITNs, or FTIs), there would need to be a 67% decline in abundance in order for VL to be eliminated (Stauch et al. 2014). Of the research conducted to date, only the FTI re- port and some of the IRS studies meet that threshold (Chowdhury et al. 2011a, Singh et al. 2012, Poché et al. 2013). Further focusing of efforts and resources could be done by implementing remote sensing and GIS data. Preliminary work done in Brazil and India modeling both climate and land data has been used to try and identify vector habitat as well as regions that may be the focus of VL outbreaks due to various weather and geo-environmental factors (Bhunia et al. 2013). While standardization of analysis methods and data acquisition are still needed, GIS and remote sensing could greatly help to tar- get high-risk areas before an outbreak occurs. Vector-control and VL-transmission stud- ies should begin to focus on combination intervention strategies as well as enhanced public education programs. If the public are unaware of the risk, the symptoms, and treatments for VL, control programs will struggle (Singh et al. 2006, Siddigui et al. 2010, Malaviya et al 2013). From what is known at this point, IRS is efficacious in quickly curbing adult sand fly populations, ITNs may have some benefit for personal protection and might also be useful if IRS is not performed correctly 100% of the time. Lastly, FTI is deleterious to both adult and J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 121 http://jad.tums.ac.ir Published Online: January 05, 2016 larval P. argentipes and has the potential to disrupt populations of exophilic sand flies. What has been lacking outside of the one study by Picado et al. (2010b), are studies that attempt to link a decline in sand fly abundance with a subsequent drop in cases of VL. A broader review of 84 studies in 22 countries involving all forms of human leishmaniasis found that only 35% measured Leishmania infection as an outcome (Stock- dale and Newton 2013). This is an issue af- flicting many vector/disease-control studies (Wilson et al. 2015). Future studies should concentrate their efforts on making this con- nection. While a decline in sand fly numbers should in theory correlate to a decline in VL infections, this link has yet to be demon- strated clearly by the research performed to date. Future work investigating the connec- tion between reduced sand fly abundance and VL infection rates as well as shifts in parasite availability and sand fly feeding be- haviors should be a priority. In combination, these tactics may work to bring sand fly numbers down quickly in the short-term, allowing for VL-patient identifi- cation and treatment. Currently, the state of Bihar is beginning tests for use of synthetic pyrethroids in place of DDT for IRS. The national roadmap laid out by the government of India emphasizes case detection and treatment as well as surveillance for PKDL. While they state the need for integrated vec- tor management, IRS remains the mainstay for vector control (NVBDP 2014). Ongoing work with sand fly breeding site identifica- tion, and implementation of more novel tech- nologies like GIS and remote sensing will greatly aid in curbing this disease. The glob- al initiative to eliminate VL in all endemic re- gions has been strong, however a coordi- nated effort between groups employing the various control tactics will be vital to see the elimination goal met. Once caseloads have been brought to 1:10,000, the use of IRS, ITNs, FTIs and all of the aforementioned technologies and trainings should be evalu- ated to determine which would be best for continued control measures. Acknowledgements We would like to thank all of the research- ers who have worked on this issue for many years whose work is represented herein. We apologize for any studies we may have left out of this report. We would also like to thank Christopher Bublitz for his careful ed- iting of this manuscript. Additionally, we extend our appreciation to the people of In- dia that allow this work to happen in their homes. References Addy M, Nandy A (1992) Ten years of kala- azar in West Bengal, part I: did post- kala-azar dermal leishmaniasis initiate the outbreak in 24-Parganas? Bull World Health Org. 70(3): 341–346. Alvar J, Yactayo S, Bern C (2006) Leish- maniasis and poverty. Trends Parasi- tol. 22(12): 552–557. Alvar J, Vélez ID, Bern C, Herrero M, Desjeux P, Cano J, Jannin J, den Boer M, WHO Leishmaniasis Control Team (2012) Leishmaniasis worldwide and global estimates of its incidence. PLoS One. 7(5): e35671. Beard J (2006) DDT and human health. Sci Total Environ. 355(1-3): 78–89. Beckvar N, Lotufo GR (2011) DDT and oth- er Organohalogen Pesticides in Aquat- ic Organisms. In: Beyer WN, Meador JP (Eds) Environmental Contaminants in Biota: Interpreting Tissue Concen- trations. Vol 2. CRC Press, New York, pp. 47–101. Bern C, Joshi AB, Jha SN, Das ML, High- tower A, Thakur GD, Bista MB (2000) Factors associated with visceral leish- J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 122 http://jad.tums.ac.ir Published Online: January 05, 2016 maniasis in Nepal: bed-net use is strongly protective. Am J Trop Med Hyg. 63(3-4): 184–188. Bern C, Hightower AW, Chowdhury R, Ali M, Amann J, Wagatsuma Y, Haque R, Kurkjian K, Vaz LE, Begum M, Akter T, Cetre-Sossah CB, Ahluwalia IB, Dotson E, Secor WE, Breiman RF, Maguire JH (2005) Risk factors for ka- la-azar in Bangladesh. Emerg Infect Dis. 11(5): 655–662. Bern C, Chowdhury R (2006) The epidemi- ology of visceral leishmaniasis in Bangladesh: prospects for improved control. Indian J Med Res. 123(3): 275–288. Bhunia, GS, Kesari S, Chatterjee N, Kumar V, Das P (2013) The burden of vis- ceral leishmaniasis in India: challenges in using remote sensing and GIS to understand and control. ISRN Infect Dis. 2013: Article ID 675846. Blus LJ (2003) Organochlorine Pesticides. In: Hoffman DJ, Rattner BA, Burton GA Jr, Cairns J Jr. (Eds) Handbook of Ecotoxicology Vol. 2. Lewis Publish- ers, New York, pp. 313–340. Boelaert M, Meheus F, Sanchez A, Singh SP, Vanlerberghe V, Picado A, Meessen B, Sundar S (2009) The poor- est of the poor: a poverty appraisal of households affected by visceral leish- maniasis in Bihar, India. Trop Med Int Health. 14(6): 639–644. CDC (2012) Malaria: Indoor residual spray- ing. Available at: http://www.cdc.gov/ malaria/malaria_worldwide/reduction/ irs.html (Accessed: 26 March 2015). Cerf BJ, Jones TC, Badaro R, Sampaio D, Teixeira R, Johnson WD (1987) Mal- nutrition as a risk factor for severe vis- ceral leishmaniasis. J Infect Dis. 156(6): 1030–1033. Chappuis F, Sundar S, Hailu A, Ghalib H, Rijal S, Peeling RW, Alvar J, Boelaert M (2007) Visceral leishmaniasis: what are the needs for diagnosis, treatment and control? Nat Rev Microbiol. 5(11): 873–882. Chowdhury R, Huda MM, Kumar V, Das P, Joshi AB, Banjara MR, Akhter S, Kroeger A, Krishnakumari B, Petzold M, Mondal D, Das ML (2011a) The Indian and Nepalese programmes of indoor residual spraying for the elimi- nation of visceral leishmaniasis: per- formance and effectiveness. Ann Trop Med Parasitol. 105(1): 31–35. Chowdhury R, Dotson E, Blackstock AJ, McClintock S, Maheswary NP, Faria S, Islam S, Akter T, Kroeger A, Akh- ter S, Bern C (2011b) Comparison of insecticide-treated nets and indoor re- sidual spraying to control the vector of visceral leishmaniasis in Mymensingh district, Bangladesh. Am J Trop Med Hyg. 84(5): 662–667. Clem A (2010) A current perspective on leishmaniasis. J Glob Infect Dis. 2(2): 124–126. Cohn BA, La Merrill M, Krigbaum NY, Yeh G, Park J-S, Zimmermann L, Cirillo PM (2015) DDT exposure in utero and breast cancer. J Clin Endocrinol Metab.100(8) 2865-72 doi: 10.1210/jc.2015-1841. Das M, Banjara M, Chowdhury R, Kumar V, Rijal S, Joshi A, Akhter S, Das P, Kroeger A (2008) Visceral leishmania- sis on the Indian sub-continent: a mul- ti-centre study of the costs of three in- terventions for the control of the sand fly vector, Phlebotomus argentipes. Ann Trop Med Parasitol. 102(8): 729– 741. Derbali M, Polyakova L, Boujaâma A, Bur- russ D, Cherni S, Barhoumi W, Chelbi I, Poché R, Zhioua E (2014) Labora- tory and field evaluation of rodent bait treated with fipronil for feed through and systemic control of Phlebotomus papatasi. Acta Trop. 135: 27–32. J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 123 http://jad.tums.ac.ir Published Online: January 05, 2016 Desjeux P (1996) Leishmaniasis. Public health aspects and control. Clin Der- matol. 14(5): 417–423. Dhiman RC, Raghavendra K, Kumar V, Kesari S, Kishore K (2003) Suscepti- bility status of Phlebotomus argentipes to insecticides in districts Vaishaii and Patna (Bihar). J Commun Dis. 35(1): 49–51. Dinesh DS, Das P, Picado A, Davies C, Speybroeck N, Ostyn B, Boelaert M, Coosemans M (2008) Long-lasting in- secticidal nets fail at household level to reduce abundance of sandfly vector Phlebotomus argentipes in treated house in Bihar (India). Trop Med Int Health. 13(7): 953–958. Dinesh DW, Kumari S, Kumar V, Das P (2014) The potentiality of botanicals and their products as an alternative to chemical insecticides to sand flies (Diptera: Psychodidae): a review. J Vector Borne Dis. 51(1): 1–7. Garlapati RB, Abbasi I, Warburg A, Poché D, Poché R (2012) Identification of bloodmeals in wild caught blood fed Phlebotomus argentipes (Diptera: Psy- chodidae) using cytochrome b PCR and reverse line blotting in Bihar, In- dia. J Med Entomol. 49(3): 515–521. Guerin PJ, Olliaro P, Sundar S, Boelaert M, Croft SL, Desjeux P, Wasunna MK, Bryceson AD (2002) Visceral leish- maniasis: current status of control, di- agnosis, and treatment, and a proposed research and development agenda. Lancet Infect Dis. 2(8): 494–501. Huda MM, Mondal D, Kumar V, Das P, Sharma SN, Das ML, Roy L, Gurung CK, Banjara MR, Akhter S, Mahe- swary NP, Kroeger A, Chowdhury R (2011) Toolkit for monitoring and evaluation of indoor residual spraying for visceral leishmaniasis control in the India subcontinent: application and results. J Trop Med. 2011: 876742. Ingenloff K, Garlapati R, Poché D, Singh MI, Remmers JL, Poché RM (2013) Feed- through insecticides for the control of the sand fly Phlebotomus argentipes. Med Vet Entomol. 27(1): 10–18. Jeronimo SMB, de Queiroz Sousa A, Person RD (2006) Leishmaniasis. In: Guerrant RL, Walker DH, Weller PF (Eds) Tropical Infectious Diseases: Princi- ples, Pathogens and Practice. Vol. 1. Churchill Livingstone Elsevier, Edin- burgh, Scotland, pp. 1095–1113. Joshi A, Narain JP, Prasittisuk C, Bhatia R, Hashim G, Jorge A, Banjara M, Kroeger AJ (2008) Can visceral leish- maniasis be eliminated from Asia? Vector Borne Dis. 45(2): 105–111. Joshi AB, Das ML, Akhter S, Chowdhury R, Mondal D, Kumar V, Das P, Kroeger A, Boelaert M, Petzold M (2009) Chemical and environmental vector control as a contribution to the elimi- nation of visceral leishmaniasis on the India subcontinent: cluster randomized controlled trials in Bangladesh, India and Nepal. BMC Med. 7: 54. Kishore K, Kumar V, Kesari S, Bhattacharya SK, Das P (2004) Susceptibility of Phlebotomus argentipes against DDT in endemic districts of north Bihar, In- dia. J Commun Dis. 36(1): 41–44. Kishore K, Kumar V, Kesari S, Dinesh DS, Kumar AJ, Das P, Bhattacharya SK (2006) Vector control in leishmaniasis. Indian J Med Res. 123(3): 467–472. Kulkarni MA, Malima R, Mosha FW, Msangi S, Mrema E, Kabula B, Lawrence B, Kinung'hi S, Swilla J, Kisinza W, Rau ME, Miller JE, Schellenberg JA, Max- well C, Rowland M, Magesa S, Drake- ley C (2007) Efficacy of pyrethroid- treated nets against malaria vectors and nuisance-biting mosquitoes in Tanzania in areas with long-term insecticide- treated net use. Trop Med Int Health. 12(9): 1061–1073. J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 124 http://jad.tums.ac.ir Published Online: January 05, 2016 Kumar V, Kesari SK, Sinha NK, Palit A, Ranjan A, Kishore K, Saran R, Kat SK (1995) Field trial of an ecological ap- proach for the control of Phlebotomus argentipes using mud and lime plaster. India J Med Res. 101: 154–156. Kumar NP, Srinivasan R, Jambulingam P (2012) DNA barcoding for identifica- tion of sand flies (Diptera: Psychodi- dae) in India. Mol Ecol Resour. 12(3): 414–420. Lengeler C (2004) Insecticide-treated bed nets and curtains for preventing ma- laria. Cochrane Database Syst Rev. 2: CD000363. Malaviya P, Hasker E, Singh RP, Van Geer- truyden JP, Boelaert M, Sundar S (2013) Village health workers in Bi- har, India: an untapped resource in the struggle against kala-azar. Trop Med Int Health. 18(2): 188–193. Malaviya P, Hasker E, Picado A, Mishra M, Van Geertruyden JP, Das ML, Boela- ert M, Sundar S (2014) Exposure to Phlebotomus argentipes (Diptera, Psy- chodidae, Phlebotominae) sand flies in rural areas of Bihar, India: the role of housing conditions. PLoS One. 9(9): e106771. Maroli M, Feliciangeli MD, Bichaud L, Charrel RN, Gradoni L (2013) Phlebotomine sandflies and the spread- ing of leishmaniasis and other diseases of public health concern. Med Vet En- tomol. 27(2): 123–147. Mascari TM, Mitchell MA, Rowton ED, Foil LD (2008) Ivermectin as a rodent feed- through insecticide for control of im- mature sand flies (Diptera: Psychodi- dae). J Am Mosq Control Assoc. 24 (2): 323–326. Mascari TM, Stout RW, Foil LD (2013) Oral treatment of rodents with fipronil for feed-through and systemic control of sand flies (Diptera: Psychodidae). J Med Entomol. 50(1): 122–125. Mondal D, Huda MM, Karmoker MK, Ghosh D, Matlashewski G, Nabi SG, Kroeger A (2013) Reducing visceral leishmaniasis by insecticide impreg- nation of bed-nets, Bangladesh. Emerg Infect Dis. 19(7): 1131–1134. Moore EM, Lockwood DN (2010) Treat- ment of visceral leishmaniasis. J Glob Infect Dis. 2(2): 151–158. Mubayi A, Castillo-Chavez C, Chowell G, Kribs-Zaleta C, Ali Siddiqui N, Kumar N, Das P (2010) Transmission dy- namics and underreporting of kala-azar in the Indian state of Bihar. J Theor Biol. 262(1): 177–185. Mukhopadhyay AK, Saxena NBL, Narasim- ham MVVL, World Health Organiza- tion Division of Control of Tropical Diseases (1992) Susceptibility status of Phlebotomus argentipes to DDT in some kala-azar-endemic districts of Bihar, India. Available at: http://www. who.int/iris/handle/10665/61452 (Ac- cessed 26 March 2015). NVBDCP (2014) National road map for ka- la-azar elimination. Available at: http:// nvbdcp.gov.in/Doc/Road-map-KA_2014. pdf (Accessed 10 June 2015). Ostyn B, Vanlerberghe V, Picado A, Dinesh DS, Sundar S, Chappuis F, Rijal S, Dujardin JC, Coosemans M, Boelaert M, Davies C (2008) Vector control by insecticide-treated nets in the fight against visceral leishmaniasis in the Indian subcontinent, what is the evi- dence? Trop Med Int Health. 13(8): 1073–1085. Perry D, Dixon K, Garlapati R, Gendernalik A, Poché D, Poché R (2013) Visceral leishmaniasis prevalence and associ- ated risk factors in the Saran district of Bihar, India from 2009 to July of 2011. Am J Trop Med Hyg. 88(4): 778–784. Picado A, Kumar V, Das M, Burniston I, Roy L, Suman R, Dinesh D, Coose- J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 125 http://jad.tums.ac.ir Published Online: January 05, 2016 mans M, Sundar S, Shreekant K, Boe- laert M, Davies C, Cameron M (2009) Effect of untreated bed nets on blood- fed Phlebotomus argentipes in kala- azar endemic foci in Nepal and India. Mem Inst Oswaldo Cruz. 104(8): 1183–1186. Picado A, Das ML, Kumar V, Kesari S, Dinesh DS, Roy L, Rijal S, Das P, Rowland M, Sundar S, Coosemans M, Boelaert M, Davies CR (2010a) Effect of village-wide use of long-lasting in- secticidal nets on visceral leishmania- sis in India and Nepal: a cluster ran- domized trial. PLoS Negl Trop Dis. 4(1): e587. Picado A, Singh SP, Rijal S, Sundar S, Ostyn B, Chappuis F, Uranw S, Gid- wani K, Khanal B, Rai M, Paudel IS, Das ML, Kumar R, Srivastava P, Dujardin JC, Vanlerberghe V, Ander- sen EW, Davies CR, Boelaert M (2010b) Longlasting insecticidal nets for prevention of Leishmania donovani infection in India and Nepal: paired cluster randomised trial. BMJ. 29 (341): c6760. Picado A, Ostyn B, Singh SP, Uranw S, Hasker E, Rijal S, Sundar S, Boelaert M, Chappuis F (2014) Risk factors for visceral leishmaniasis and asympto- matic Leishmania donovani infection in India and Nepal. PloS One. 9(1): e87641. Poché D, Garlapati R, Ingenloff K, Remmers J, Poché R (2011) Bionomics of phlebotomine sand flies from three vil- lages in Bihar, India. J Vector Ecol. 36(1): S106–117. Poché RM, Garlapati R, Elnaiem DEA, Per- ry D, Poché D (2012) The role of Pal- myra palm trees (Borassus flabellifer) and sand fly distribution in northeastern India. J Vector Ecol. 37(1): 148–153. Poché RM, Garlapati R, Singh MI, Poché DM (2013) Evaluation of fipronil oral dosing to cattle for control of adult and larval sand flies under controlled con- ditions. J Med Entomol. 50(4): 833–837. Rahman KM, Islam S, Rahman MW, Kenah E, Ghalib CM, Zahid MM, Maguire J, Rahman M, Haque R, Luby SP, Bern C (2010) Increasing incidence of post- kala-azar dermal leishmaniasis in a population-based study in Bangladesh. Clin Infect Dis. 50(1): 73–76. Ramesh V, Mukherjee A (1995) Post-kala- azar dermal leishmaniasis. Int J Der- matol. 34(2): 85–91. Ranjan A, Sur D, Singh VP, Siddique NA, Manna B, Lal CS, Sinha PK, Kishore K, Bhattacharya SK (2005) Risk fac- tors for India kala-azar. Am J Trop Med Hyg. 73(1): 74–78. Sharma VP, Dhiman RC (1993) Neem oil as a sand fly (Diptera: Psychodidae) re- pellent. J Am Mosq Control Assoc. 9(3): 364–366. Sharma U, Singh S (2008) Insect vectors of Leishmania: distribution, physiology and their control. J Vector Borne Dis. 45(4): 255–272. Sharpe RM, Stewart D (2004) How strong is the evidence of a link between envi- ronmental chemicals and adverse ef- fects on human reproductive health? BMJ. 328(7437): 447–451. Siddigui NA, Kumar N, Ranjan A, Pandey K, Das VN, Verma RB, Das P (2010) Awareness about kala-azar disease and related preventative attitudes and prac- tices in highly endemic rural area of India. Southeast Asian J Trop Med Public Health. 41(1): 1–12. Singh R, Das RK, Sharma SK (2001) Re- sistance of sandflies to DDT in kala- azar endemic districts of Bihar, India. Bull World Health Org. 79(8): 793. Singh SP, Reddy DC, Mishra RN, Sundar S (2006) Knowledge, attitude, and prac- tices related to kala-azar in rural area of Bihar state, India. Am J Trop Med J Arthropod-Borne Dis, June 2016, 10(2): 113–126 D Bublitz et al.: Measures to Control … 126 http://jad.tums.ac.ir Published Online: January 05, 2016 Hyg. 75(3): 505–508. Singh SP, Hasker E, Picado A, Gidwani K, Malaviya P, Singh RP, Boelaert M, Sundar S (2010) Risk factors for vis- ceral leishmaniasis in India: further ev- idence on the role of domestic animals. Trop Med Int Health. 15(S2): 29–35. Singh RK, Mittal PK, Dhiman RC (2012) Insecticide susceptibility status of Phlebotomus argentipes, a vector of visceral leishmaniasis in different foci in three states of India. J Vector Borne Dis. 49(4): 254–257. Sparling DW (2010) Ecotoxicology of Or- ganic Contaminants to Amphibians. In: Sparling DW, Linder G, Bishop CA, Krest SK (Eds) Ecotoxicology of Amphibians and Reptiles Vol. 2. CRC Press, New York, pp. 261–288. Stauch A, Duerr HP, Picado A, Ostyn B, Sundar S, Rijal S, Boelaert M, Dujar- din JC, Eichner M (2014) Model-based investigations of different vector-re- lated intervention strategies to elimi- nate visceral leishmaniasis on the India subcontinent. PLoS Negl Trop Dis. 8(4): e2810. Stockdale L, Newton R (2013) A review of preventative methods against human leishmaniasis infection. PLoS Negl Trop Dis. 7(6): e2278. Thakur CP (2000) Socio-economics of vis- ceral leishmaniasis in Bihar (India). Trans R Soc Trop Med Hyg. 94(2): 156–157. Thakur CP (2007) A new strategy for elimi- nation of kala-azar from rural Bihar. India J Med Res. 126(5): 447–451. van den Berg H (2009) Global status of DDT and its alternatives for use in vector control to prevent disease. Envi- ron Health Perspect. 117(11): 1656– 1663. Wasserberg G, Poché R, Miller D, Chenault M, Zollner G, Rowton ED (2011) Im- idacloprid as a potential agent for the systemic control of sand flies. J Vec Ecol. 36(S1): 148–156. WHO (2010) Control of the leishmaniases. World Health Organization technical report series. Available at: http:// whqlibdoc.who.int/trs/WHO_TRS_94 9_eng.pdf (Accessed 22 March 2015). Wilson AL, Dhiman RC, Kitron U, Scott TW, van den Berg H, Lindsay SW (2014) Benefit of insecticide-treated nets, curtains and screening on vector borne diseases, excluding malaria: a systematic review and meta-analysis. PLoS Negl Trop Dis. 8(10): e3228. Wilson AL, Boelaert M, Kleinschmidt I, Pinder M, Scott TW, Tusting LS, Lindsay SW (2015) Evidence-based vector control? Improving the quality of vector control trials. Trends Parisi- tol. 31(8): 380–390.