5- Dr.Basseri RTL_2_ Iran J Arthropod-Borne Dis, 2010, 4(2): 35–41 KH Shahandeh et al.: Mosquito Vector Biting … 35 Original Articles Mosquito Vector Biting and Community Protection in a Malarious Area, Siahoo District, Hormozgan, Iran KH Shahandeh1, *HR Basseri 2, A Pakari 3, A Riazi 2 1Social Development and Health Promotion Research Center, Tehran University of Medical Sciences, Tehran, Iran 2Department of medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 3Institute of Public Health, Bandar-Abbas Center of Health Research and Education, Tehran University of Medical Sciences, Tehran, Iran (Received 3 Jul 2010; accepted 3 Aug 2010) Abstract Background: Use of bed-net continues to offer potential strategy for malaria prevention in endemic areas. Local communities are indispensable during design and implementation stages. Methods: A cross-sectional study of 192 randomly selected inhabitants was carried out in malarious zone, Siahoo direstrict, Hormozgan Province, southern Iran. In addition, we monitored human landing periodicity of main malaria vectors and as well as self-protection of inhabitant in the study area for a period of one transmission season between April to October 2006. Results: The biting activities were seen throughout the whole night for three malaria vectors, Anopheles fluviatilis, An. stephensi and An. dthali, and An. fluviatilis exhibiting bimodal peaks, the first at midnight (0:00−1:00) and the other before dawn (5:00−6:00 am) but the maximum biting activity of An. stephensi was occurred at second quarter of night (11:00−12:00 pm). The majority of interviewers (83.3%) knew that malaria was transmitted by mosquitoes and 70.3% of them stated that bed-net is the best control measures. Most subjects (62%) did not have a mosquito net. Conclusion: Study subjects were aware of an association between mosquito bite and malaria transmission. Health workers at different levels of the health care delivery system should disseminate relevant information about self- protection to help community members to be involved more in malaria control. Keywords: Malaria, Community Protection, Mosquito Bite, Iran Introduction In spite of more than 45 yr malaria control programming, malaria remains prevalent in southern and southeastern Iran. During the last six yr, 15000 to 25000 cases have been reported each year in Iran and more than 85% of them occurred in the south and southeast of the country (Department of communicable Disease Control, personal communication). The annual parasite index (API) is seven per 1000 inhabitants in the endemic area (Raeisi 2006). Several factors, such as presence of insecticide resistance among vectors (Dinparast-Jadid et al. 2006), parasite drug resistance (Edrissian et al. 1993, Edrissian 2006) and socio-eco- nomical problems (Banguero 1984, Raeisi 2006), have made eradication in this area im- possible. However, several main inhibitor fac- tors have been defined in Hormozagan Prov- ince, which restricted malaria control programs in that particular area (Masoumi Asl et al. 2003). Generally, prevention of malaria through better knowledge and awareness is the ap- propriate way to keep malaria disease away. In addition, knowledge of host feeding pattern *Corresponding author: Dr Hamid Reza Basseri, Email: Basserih@sina.tums.ac.ir Iran J Arthropod-Borne Dis, 2010, 4(2): 35–41 KH Shahandeh et al.: Mosquito Vector Biting … 36 and resting behavior of mosquito vectors are important for understanding the host-vector relationship and dynamic of disease transmis- sion and for development of control strate- gies (Singh 1998, Chaves et al. 2010). The predominant mosquito species in the southern Iran are Anopheles stephensi, An. culicifacies and An. fluviatilis which play the major role in malaria transmitting (Zaim et al. 1993, Vatandoost et al. 2003, Basseri et al. 2008). Vector control activities in south and southeast of Iran are mainly restricted to indoor residual spraying (IRS) in selected endemic localities with pyrethroids and lar- viciding with Bacillus thuringiensis, (Minis- try of Health and Medical Education, Iran 2008). In addition recently by planning ma- laria elimination program, self-protection us- ing bed net has been more considered. With this background, this study is pro- posed to find the sleeping behavior of resi- dent and the ratio of man-vector contact in the area where exophilic vector such as An. fluviatilis is highly active and therefore using indoor residual spraying is so limited. Al- though, it has been planned to used long lasting Impregnated bed net in south of Iran by health authorities in local provinces, therefore, the results of this study can show more strengthens and weakness of using bed net in that particular area. Materials and Methods Study area This study was performed in Siahoo dis- trict located in about 90 km north of Bandar- Abbas city, Hormozgan Province (25◦24'–28◦57 'N and 52◦41'–59◦15' E) over a period of six months, during 2007 and 2008. The tempera- ture reaches to maximum 35° C in highlands and to 40° C in plan areas during summer but it rarely decline to 5-10° C during winter. Gener- ally, the area has a subtropical climate and is prone to seasonal malaria transmission. Hor- mozgan comprises three regions of differing ge- ography, the coastal region in the south, a mountainous region in the north, and a rural plateau or plains region in the centre. Siahoo is a rural county located in mountainous area with a total population about 10000. It is an ag- ricultural region irrigated by rivers, deep wells, and cement pools, which are the main of breed- ing sites for mosquitoes. The annual rainfall ranged from 80 to 100 mm. Features contribut- ing perennial transmission in the areas are mainly due to population movement and spe- cially form west border of province, Sistan- Baluchistan. The malaria vectors are very much potent with high anthropophilic index and frequent man biting habits and above all presence of varying degree of resistance to insecticides and drugs. Sampling technique A cross-sectional study was designed for the study area. Ten percent of target groups including residents, who attended to malaria clinics in Siahoo Health Centers, were se- lected by systematic random sampling. Then they interviewed to obtain knowledge, attitude and behavior of them about mosquito biting and self-protection against it and malaria transmission. Structure interview forms were obtained from participants. The structure in- terview form was explained to local staff in advance. The completed forms and records were then checked and collected by technicians at the Health Research Center of Bandar-Abbas (Institute of Public Health, Tehran University of Medical sciences). Data Collection; methods, instruments used, measurements: Structure questions consisted of open and closed questions and designed in several parts, including participants' details, house structure, sleeping behavior, mobility, self-protection, his- tory of malaria infection and treatments used, facilities, access to health services. The inter- views were conducted in the native accent and dialects by questioners. The validity of Iran J Arthropod-Borne Dis, 2010, 4(2): 35–41 KH Shahandeh et al.: Mosquito Vector Biting … 37 questions was checked in Statistics Department, School of Public Health, and Tehran Univer- sity of Medical Sciences. Data were ana- lyzed under supervision of the Statistics De- partment, School of Public Health. Ethical approval for the research was obtained from the Tehran University of Me- dical Sciences research Ethics Committee. In- formed consent was obtained from all par- ticipants themselves. Anonymity was assured to the participants, and it was explained to them that transcripts would not have identifiable features and would be kept in a secure location. Mosquito collection (mosquito landing catch) Activity of malaria vectors was surveyed by human landing catch by interval two weeks during seasonal activity of mosquitoes, from 10th of April to 20th of October 2006. Human landing catch was carried out continuously during whole night from sunset since sunrise (19:00–06:00 h) by trained staff using oral aspirators (Service 1976). Two human volun- teers of native people acted as baits while wearing their normal clothing. The exposed body surfaces were searched and the mos- quitoes that were attempting to bite were col- lected using oral aspirators by insect collectors. During human landing collection, collector workers shift every two hours. The hourly collection of mosquitoes were kept and brought to laboratory alive. They were anesthetized by chloroform and identifies based on spe- cies keys of Smart (2003). Finally, the human biting rate was calculated directly from hu- man landing catches as the average number of bites per person per night. Results Demographical information and knowledge of respondents In this study, the valid questionnaire was 192 respondents. The mean age of subjects was 31 yr (range 12 to 69 yr; standard devia- tion 11 yr; median 30 yr). Near one third of respondents were females and totally, less than one-fifth (19.2%) of participants were illiterate. The demographic characteristics of the interviewees are showed in Table 1. Mosquito bite was mentioned to be the main 'cause' of malaria by 83.3% of the re- spondents. Other mentioned causes were dirty water (10.9%), and food (0.5%) and 3.6% of respondents said they do not know (Table 2). When asked about the ways of preventing malaria, 70.3% recognized using mosquito nets, 89% drying stagnant water around their homes, 4.2% using screens on doors and windows and 68.7% insecticides as control measures. Practice for biting protection Majority of respondents (62 %) reported that not having bed net. Generally, all re- spondents with bed net indicated that they used bed nets more often from beginning of April to end of September but them majority of them used nets from evening and night and only 4.1% of those who owner of bed net, used it during whole night (Table 3). Near 40% of total interviewers stated that they always used bed-net and only a few of them sometime slept under bed-net. The major- ity of respondents do not have mosquito screen on windows (75%) and doors (99%). Mosquito biting periodicity Biting activities of the mosquito vectors are shown in Fig. 1. Anopheles fluviatilis, An. stephensi and An. dthali were highly active during whole night. The mosquitoes started bit- ing continuously from sunset to sunrise (Fig. 1). Anopheles fluviatilis was predominantly cap- tured on human baits followed by An. ste- phenis and An. dthali at relatively lower po- pulation. Landing rate of An. fluviatilis with average of 11.2 mosquitoes per human bait per night was slightly higher than others were. The average number of An. stepehnsi cap- tured on human bait per night was 4.1 and for An. dthali was 1.5. The peaks of landing for An. fluviatilis and An. stephensi was Iran J Arthropod-Borne Dis, 2010, 4(2): 35–41 KH Shahandeh et al.: Mosquito Vector Biting … 38 occurred at approximately midnight followed with a short peak before sun rise but An. dthali started landing earlier at begging of sunset and its activities declined at midnight. Table 1. Main demographic characteristics of the study sample (participants) Characteristic No. % Age (years) <15 18 9.4 16-25 63 32.8 26-45 81 42.2 46+ 30 15.6 Sex ratio Males 125 65.1 Females 67 34.9 Education level Illiterate 31 16.1 Literate 161 83.9 Table 2. Knowledge of participants about transmission route and control measures Variable Frequency % Route of transmission Mosquitoes 160 83.3 Dirty water 21 10.9 Polluted food 1 0.5 Other incorrect 3 1.6 Don’t know 7 3.6 Control measures Using mosquito net 135 70.3 Using door/window screen 8 4.2 Taking drugs regularly 10 5.2 Drying stagnant water 171 89.0 Using insecticides 132 68.7 Others 22 11.4 Table 3. Mosquito biting behaviors practiced by participants Variable Frequency % Availability of mosquito net Have mosquito net 73 38.0 Frequency of net use Always 65 33.9 Sometimes 8 4.1 Time of net use Night 27 14.0 Evening and night 46 24.0 Use of screens On windows 25 13.0 On doors 1 0.5 0 0.5 1 1.5 2 2.5 18-19 19-20 20-21 21-22 22-23 23-24 24-01 01-02. 02-03. 03-04. 04-05. 05-06. Time M e a n o f m o s q u it o b it e s p e r h e u m a n b a it An. fluviatilis An. stephensi An. dthali Fig. 1. Biting activities of main malaria vectors during night on human bait in Siahoo district, Hormozgan. Iran J Arthropod-Borne Dis, 2010, 4(2): 35–41 KH Shahandeh et al.: Mosquito Vector Biting … 39 Discussion Although the ratio of literacy among participants was relatively high, it is neces- sary to provide people with adequate infor- mation about the role of mosquito vectors in transmission and incidence of malaria in their area and its complications, to increase public awareness about the importance of malaria vector. However, the study revealed that in Siahoo, community comparatively recognized the role of mosquitoes in malaria transmis- sion and knowledge of malaria was moderate but the malaria prevention activity by people was relatively poor. Nevertheless low level of educational status, rampant ignorance about the cause, treatment, and prevention of ma- laria, poor socio economic background contrib- utes a lot to the cause of malaria but fortu- nately, adequate health care services can make the disease infection declined in the region (Banguero 1984). The biting behavior of any mosquito species is a biologic characteristic and could vary among species. The biting activities of An. fluvialitis and An. stephensi were seen throughout the whole night from dusk to dawn. Thus, the residents in Siahoo region are ex- posed to the vector bites even before bedtime or using bed-net. Anopheles fluvialitis and An. stephensi are principal vectors in south slop of Zagrus mountain chain (Manouchehri et al. 1976, Vatandoost et al. 2006). Anopheles fluvialitis has been recognized as a wild ma- laria vector with high anthropophilic index (Nanda 2000, Basseri et al. 2005). In con- trary, An. stephensi is a domestic mosquito with endophilic and endophgic behaviour in Hormozgan Province (Vatandoost et al. 2006). In the present study, An. fluviatilis was predominant among the mosquitoes collected in the human landing catches. Controlling of this species is ecologically and logistically chal- lenging. The options for the control of this species are very limited but self-protection methods such as using insecticide integrated bed-net could be more convenient way to control malaria transmission. In addition, hu- man-vector contact could be reduced by a adjusting the time of bed-net use (Binka 1998). Thus insecticide integrated bed-net can be targeted approach of adopting personal pro- tective measures in Siahoo area while An. fluviatilis avoid feed or resting in indoor places (Edalat 1998). However, these meas- ures need to be encouraged among the native population (Stephens 1995). They could be sensitized and motivated by health workers to adopt such measures. The key to imple- mentation of personal protective measures are health education and socioeconomic devel- opment, which can cause the annual infective biting rate and reduce transmission potentials. We conclude that the biting periodicity of An. fluvialitis is bimodal peaks and the peak biting activity of this mosquito coin- cides with the sleeping time of inhabitant. The risk of acquiring an infection based on parity status could be elucidated towards the dusk since dawn hours, as shown by the bi- modal peaks of biting activity of mosquitoes, namely, a minor peak at midnight. Therefore human-vector contact could be reduced by a time and space targeted approach of adopt- ing personal protective measures such as protective (Yadav et al. 1999, Takken 2002). In conclusion, regular and periodic inter- vention in the form of health education to bring an attitudinal and behavioral change and pro- vision of better health care services in the Siahoo area can bring qualitative change in control of malaria in the region. Acknowledgements The authors would like to thank personnel of Bandar-Abbas Training and Research Center for their kind assistances and Institute of Public Health Research. 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