J Arthropod-Borne Dis, June 2014, 8(1): 102–107 S Bokaie et al.: Prevalence and Epizootical … 102 Short Communication Prevalence and Epizootical Aspects of Varroasis in Golestan Province, Northern Iran Saeid Bokaie 1, *Laleh Sharifi 2, Majid Mehrabadi 3 1Department of Epidemiology, Veterinary Medicine Faculty, University of Tehran, Tehran, Iran 2Immunology, Asthma and Allergy Research Institute, Tehran University of Medical Sciences, Tehran, Iran 3Graduated from Azad Islamic University, Garmsar Branch, Garmsar, Iran (Received 20 Nov 2011; accepted 15 May 2013) Abstract Background: The Varroa destructor mite is considered as a major pest of honey bees Apis mellifera. The rapid spread of Varroa mites among bee colonies may be due to several factors, including drifting of infested bees, movement of bee swarms, and robbing of weakened colonies. Disease spread and predisposing the infested bees to other diseases lead to high economic losses in beekeeping industries. The aim of this study was to determine the prevalence of and evaluate some managing factors in Golestan Province in Iran in 2008. Methods: According to the records of Agricultural Research Center, 80 infested beekeeping centers identified and a questionnaire consists of managing factors for each center has been designed. All data were recorded and analyzed by SPSS software to calculate χ2 test. Results: Among 80 apiculture centers, 72 centers (92%) were infested to Varroa and hive density of 90.6% of the centers was 31–60 hives in one center (P= 0.324). All of the apiculture centers had more than 6 km distance to near- est beekeeping center (P= 0.687). Amongst bee keepers 15(93.8%) had low literacy level (P= 0.479) and 26(89.7%) had 5–10 years experience in beekeeping (P= 0.953). Conclusion: We can conclude that because of the high prevalence of the disease, the usual methods of prevention are not effective. This high prevalence emphasizes that we are very far from a solution for Varroa infestation and extra researches on mite biology, tolerance breeding, and Varroa treatment is immediately required. Keywords: Apis mellifera, Varroa destructor, Honey bee, Iran Introduction The new worldwide distributed and hemophagous mite Varroa destructor is con- sidered as a main pest of honey bees Apis mellifera. Before year 2000, V. destructor was understood to be Varroa jacobsoni (Ander- son and Trueman 2000) which successfully shifted from the original host, A. cerana to the Western honey bee, A. mellifera. (Rath 1999). The details of the host shifting phe- nomenon are unclear. Varroa destructor acts as a vector of different bee viruses. Until now 18 different viruses have been identified in honey bees (Chen and Siede 2007). Numer- ous of bee viruses can be transmitted by V. de- structor such as Acute Bee Paralysis Virus (ABPV), Israeli Acute Paralysis Virus (IAPV), Kashmir Bee Virus (KBV), Sacbrood Virus (SBV), and Deformed Wing Virus (DWV) (Boecking and Genersch 2008). Before the appearance of Varroa mites in A. melifera, viral diseases were minor troubles for honey bee health (Allen et al. 1986, Bailey and Ball 1991, Bowen-Walker et al. 1999, Yue and Genersch 2005). At a short time V. destruc- tor has worldwide geographical distribution and we can not find a country free of this disease rather than Australia. The economic burden of this ectoparasite is high. Disease *Corresponding author: Dr Laleh Sharifi, E-mail: lalehsharifi@yahoo.com http://jad.tums.ac.ir Published Online: December 18, 2013 J Arthropod-Borne Dis, June 2014, 8(1): 102–107 S Bokaie et al.: Prevalence and Epizootical … 103 distribution and predisposing the infested bees to other diseases lead to high economic loss- es in beekeeping industries. In addition, Varroa mite may intensify the problems of pollina- tion in future time (De la Rua et al. 2009). Varroa females start to reproduce by en- tering the brood cells of last-stage worker or drone larvae, normally within 20–40 hours before the cells are sealed (Boot et al. 1992). About 60 h after the bee cell is capped; the adult female mite puts her first egg and can produce over 10 progeny (Sammataro et al. 2000). The adult female mite and progeny feed on the hemolymph of pupae from a sin- gle feeding site (Kanbar and Engels 2003). All reproduction of Varroa occurs in the brood cells, and only the adult females sur- vive after the bee emerges. Some immature females, eggs (rarely), and males are left and removed by the nurse bees when the bee emerges. Varroa mites suck the hemolymph from adults and developing pupae of honey bees, thereby weakening the bees and reduc- tion their life length. The rapid spread of Varroa mites among bee colonies is due to a number of factors such as drifting of dis- eased bees, movement of bee swarms, and robbing of weakened colonies (de Jong 1997). In addition, migratory beekeeping practices and the importation of infested bees lead to rapid distribution of Varroa mites (Sammataro et al. 2000). Application of synthetic acaricides has been the main way for controlling the pest. But the intensive use of many chemical sub- stances against the mites resulted in the in- crease of resistance and decrease of their ef- ficiency (Milani 1999) and contamination of products such as honey and beeswax (Wallner 1999). The problems of chemical acaricides encourage the scientists to find new and saf- er ways control of Varroa. Natural products such as essential oils offer a highly desirable alternative to synthetic products. These sub- stances are used increasingly because they are generally inexpensive and have fewer health hazards to both man and honeybees (Isman 2000). Various alternative ways for managing the mite have been investigated (Imdorf et al. 1995, Fries 1997, Thomas 1997, Calderone 2005). Most of them are suggesting non- chemical methods for reaching lower occur- rence of mite infestation in beehives (Imdorf et al. 1999). One of these non-chemical meth- ods is use of formic acid that has received great consideration because of its activity against V. destructor (Calderone 2000, Currie and Gatien 2006). Based on the veterinary organization pro- tocol in Iran the bee hives with ≤ 5% infes- tation of V. destructor must be treated with standard treatments such as Formic Acid®, Api Life Var®, Apiguard®, Apistan® and Apivar®. The objectives of this study were to deter- mine the prevalence of V. destructor and evaluating the effect of the hygienic factors in infestation rate in Golestan Province of Iran. This province with temperate and wet macro climate is one of the most important sites of beekeeping industry in Iran. Materials and Methods All beekeeping centers were identified in Golestan Province according to the infor- mation of the Agricultural Research Center. Due to protocol of the Iranian Veterinary Or- ganization, Varroa sampling was done every season and 5% of hives in each beekeeping center were investigated. Beehives with less than 5 honey-combs were excluded from sam- pling. A questionnaire consisted of managing and hygienic factors were filled for each beekeeping center. Questions included dis- tance to the nearest apiculture center, alti- tude of apiculture center from the sea level, use of guard wall around the beekeeping cen- ter, migration situation, numbers of hives, the height of hives from the ground, distance between hives, disinfection procedures, and http://jad.tums.ac.ir Published Online: December 18, 2013 J Arthropod-Borne Dis, June 2014, 8(1): 102–107 S Bokaie et al.: Prevalence and Epizootical … 104 methods to provision of pollen, wax, apicul- ture equipments, queen and water supplying. Literacy and experience levels of bee keep- ers were asked also. All data were recorded and analyzed by SPSS software version 15 to calculate χ2 test and fisher exact test. P values less than 0.05 were considered as significant level. Results Among 80 apiculture centers, 72 centers (92%) were infested by Varroa mite. The hive density of 90.6% of centers was 31–60 hives/ center (P= 0.324). All of the apicul- ture centers had more than 6 km distance to nearest beekeeping center (P= 0.687). Fire have been used to disinfect the equipments in 54 (90%) of studied centers (P= 1.000). Fifty eight infected centers (90.6%) had migrated beehives (P= 0.657). Amongst beekeepers 15(93.8%) had low lit- eracy level (P= 0.479) and 26(89.7%) had 5–10 years experience in beekeeping (P= 0.953). In Table 1 the association between Varroa infestation of beekeeping centers and the al- titude of apiculture center from the sea level, the height of beehives from the ground, dis- tance between beehives and use of guard wall around the beekeeping center, have shown. The methods for provision of pollen, wax, apiculture equipments, queen and water sup- ply have been shown in Table 2 and their relations with varroasis are in the same table. Table 1. The relations between varroasis and the altitude of apiculture center, the height of hives, distance between hives and use of guard wall VariablesVarroasis Positive Negative P value Altitude of apiculture center ≤800m 47(90.4%) 5(9.6%) P= 1.000 >800m 25(89.2%) 3(10.8%) Height of hives from the ground surface 10–25cm 69(89.6%) 8(10.4%) P= 0.0284* 26–40cm 3(100%) 0(0%) Distance between hives ≤50cm 63(90%) 7(10%) P= 1.000 >50cm 9(90%) 1(10%) Use of guard wall Yes 19(79.2%) 5(20.8%) P= 0.0485* No 53(95%) 3(5%) *P< 0.05 is significant Table 2. The relation between varroasis and the use of pollen in apiculture, source of pollen, water, wax, equipments, and queen Variables Varroasis Positive n (%) Negative n (%) P value Use of additional pollen Yes 62(89.8) 7(10.2) P= 0.00011* No 10(91) 1(9) Purchase pollen from other apiculture centers Yes 65(91.5) 6(8.5) P= 0.2201 No 7(77.7) 2(22.3) Purchase wax from other apiculture centers Yes 58(89.2) 7(10.8) P= 1.000 No 14(93.3) 1(6.7) Purchase second hand equipments from other apiculture centers Yes 24(92.3) 2(7.7) P= 1.000 No 48(88.9) 6(11.1) Purchase queen from other apiculture centers Yes 32(84.2) 6(15.8) P= 0.1414 No 40(95.2) 2(4.8) Source of water River 63(88.7) 8(11.3) P= 0.0008* Non river 9(100) 0(0) *P< 0.05 is significant http://jad.tums.ac.ir Published Online: December 18, 2013 J Arthropod-Borne Dis, June 2014, 8(1): 102–107 S Bokaie et al.: Prevalence and Epizootical … 105 Discussion According to the results, this high prevalence of infestation shows the high spread of V. destructor in beekeeping centers in Golestan Province. This occurrence is similar to other sites of the world that had reported, the east- ern coastal region of the USSR in 1952, Pakistan in 1955, Japan in 1958, China in 1959, Bulgaria in 1967, Paraguay in 1971, Germany in 1977 (Ruttner and Ritter 1980), United States in 1987 (De Guzman and Rinderer 1999). Today, V. destructor has glob- al distribution, but according to the reports published by Australian Government (http:// www.daff.gov.au/qis/quarantine/pests-diseases/ honeybees) it has not yet been found in Aus- tralia. In this study we showed that heights of hive from the ground level associated to varroais prevalence. Distance from the ground sur- face can affect the humidity of brood cells and influence the mite reproduction. We found a significant relation between varroasis and use of additional pollen for hives in beekeeping centers. In addition we found that the infestation rate of bee-keeping cen- ters that supply their water from the river are less than centers which provide water from other routs also use of guard wall around the apiculture center was related to lower infes- tation rate of Varroa. The micro-climatic con- ditions inside the colony are affected by out- side factors including temperature, humidity or the accessibility of pollen and nectar. This may influence the proportion of non-repro- ducing mites (Eguaras et al. 1994, Garcia-Fer- nandez et al. 1995, Kraus and Velthuis 1997, Moretto et al. 1997). According to the non-significant results of the effect of bee-keepers’ literacy and expe- rience level in prevention of disease, ineffi- ciency of hygienic factors such as having suitable distance to other beekeeping centers and decreasing hive density in a center (num- ber of hives), the altitude of apiculture center from the sea level and distance between bee- hives, it can be concluded that the usual meth- ods of Varroa prevention are not effective. However the ways to provision pollen, bee wax, equipments, and queen had not any in- fluence on Varroa infestation rate. Use of Varroa tolerant honey bees and chem- ical and biological methods of Varroa treat- ments are suggested as important controlling ways. The control of mite reproduction is considered the most effective tool for the host to prevent the growth of a Varroa popu- lation within the colony (Fries et al. 1994). 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