7- Rafinejad_RTL Iranian J Arthropod-Borne Dis, (2007), 1(1): 52-57 J Rafinejad et al.: Systematic, Bioecology and… 52 Original Article Systematic, Bioecology, and Medical Importance of Widow Spiders (Lathrodectus spp.) in Khorasan Province, Iran *J Rafinejad 1, S Tirgari 1, F Biglarian 2, K Shemshad 3 1 Dept. of Medical Entomology and Vector Control, School of Public Health and Institute of health Research, Medical Sciences/ University of Tehran, Iran 2 Ministry of Education and Training, Zone 2, Tehran, Iran 3Department of Entomology, Science and Research Branch, Islamic Azad University, Tehran, Iran (Received 20 Oct 2006; accepted 15 Jan 2007) ABSTRACT Following the hospitalization of 195 individuals due to the spider bite in 1995 and three cases of recorded death in the year of 1993 which were referred to Emam Reza Hospital in Mashad, the present study was undertaken on bionomics and medical importance of Lathrodectus spp in Khorasan Province, during 1995-2005. A total cases of 195 bites were studied composing of 70.8 % males and 29.2% females. The most prevalence cases were observed in mid age (20-55 years old) and particularly among farmers (36.4%). A total number of 216 adult widow spiders and 258 egg sacs were collected from their habitats in different localities of 15 counties in the province. The following species have been recognized: Lathrodectus tredecimgottatus (62%), L. dahli (32%), L. geometricus (5%) and L. pallidus (1%). Here is the first report on the occurrence of males of L. pallidus as well as both sexes of L. trdecimgottatus and L. geometricus in the country. The sex ratio among collected specimens was 88% and 12% female and male, respectively. Summer provides the most suitable and favorable climatic condition for the activities of these spiders. However 65% of spiders were collected in this season. Among different cities, Mashad had (60%) the most reported cases in the study area. Foot was more injured than other parts. 96.5% of patients exhibited localized pain from which only 2% had no pain in the bitten part and 87% had a generalized pain in whole body. Keywords: Black widow spiders, systematic, Iran INTRODUCTION Phylum arthropoda includes about 10 to 20 classes, depending on the classification adopted. Spider considered as one order of Arachnida (sub class) and class of Aranea (Cambridge 1902, Forster 1968, Jung and White 1993). These crea- tures normally spend their life cycle near hu- man dwelling and work on farms. Latrodectus spp. are known as black widow spiders (Garb et al. 2004). Among 3500 spider species, widow spider is considered as one of the most poison- ous and dangerous spiders the entire world (Pom- mier et al. 2005). It has a wide distribution in the world and occurs mainly in south parts of former Soviet Union, Middle East and Mediterranean regions (Kaston 1970, Levi 1986, Lotz 1994, Miller 1993, Robert 1985, Zukowski 1993). The widow spiders characteristically spin tangled webs, which look similar to spun cotton candy. Their webs are usually built in or beneath objects close to the ground such as under porches, under foun- dations of buildings, the lose bark of trees, and in basements (Nicholson and Graudins 2002, Blackledge et al. 2005). The bite of the black widow is painful and may cause death if medi- cal attention is not sought immediately. The *Corresponging author: Dr J Rafinejad Tel: +98 21 66465404, (Ext: 2179), E-mail: jrafinejad@yahoo.com Iranian J Arthropod-Borne Dis, (2007), 1(1): 52-57 J Rafinejad et al.: Systematic, Bioecology and… 53 venom of this spider is highly neurotoxic and respiratory failure can occur if appropriate medi- cations are not administered at once. Latrodectus is exclusively carnivorous and antagonistic. Ordinarily it feeds on insects; however, it also consumes wood lice, diplopods, chilopods and other arachnids (Garb et al. 2004). In Iran espe- cially northeast of country (Khorasan Province) there were several reports of Latradoctism. Spe- cies of this genus were responsible for 3 cases of death in 1993. There were 195 hospitaliza- tion cases due to the spider bite in 1995. Most of cases were reported from 6 counties includ- ing Mashad, Sabzevar, Neishabour, Sarakhs, Qoochan and Chenaran. However, an attempt was made during 1995-2000 on the demographic and clinical characteristics of widow spider bite in order to highlight the systematic, ecology and biology of Latrodectus spp. and its medical importance in the study area because of the im- portance of the Khorasan Province for agricul- ture, industry and elsewhere in Iran and also the existence of farm areas which provide suitable habitats for spiders. This investigation gives new data which will be valuable for future planning control and solving the public health problem, identification of different species of black widows, and differ- ent aspects of systematic such as feeding, egg sac, seasonal abundance, natural habitat, repro- duction, longevity, nidification, tarnished and shape of net. MATERIALS AND METHODS Study area This investigation was carried out in 15 counties in the north and central Khorasan Prov- ince, located in north east of Iran (Map 1) and according to zoogeography distribution it is lo- cated in the Palearctic Region. Spider collection All the specimens were collected by direct method from different parts of the study areas including flagging vegetation, hedgerow of farms, crevices and cracks of walls surrounded of gardens and rodents holes. After collection, specimens were transferred in to the holding tubes including alcohol (9 parts) and formalin (1 part). For species identification several parameters including morphology, biol- ogy and ecology of spiders and date, place, col- lector, habitats, number of spiders in each net, number of egg sac, distance of nest from earth, feeding preference and distance to water source and having net and clinical characteristics of widow spider bite have been considered. Recog- nition was carried out by morphological charac- teristics according to the international standard taxonomic key identification (Robert 1985, Wil- son and King 1990). The data were analyzed using SPSS program. RESULTS In this research a total of 216 adult spiders and 258 egg sacs were collected from the study areas. One hundred ninety one specimens were female (88.43%) and 25 were male (11.57%). The frequency of spiders were more prevalent in Bojnourd County with 49 cases( 22.69%) and Chenaran with 46 cases(21.30%) and the lowest cases was seen in Fariman (0.93%) and Tor-batejam (1.85%). The identified species were as follows: L. tredecimgottatus (62%) was the most prevalent. One hundred seventeen specimens were female (87.31%). This species was more prevalent in Bojnourd (26.5%) and Chenaran (23.08%) and less prevalent in Kashmar, Gona- bad, Fariman and Torbatejam with 1.71% in each county. L. dahli with 32% prevalence had the second abundance. Sixty two specimens were female (91.18%). This species was more preva- lent in Bojnourd and Chenaran (22.58%) and less prevalent in Kashmar, Shiravan, and Tor- bateheidarieh with 1.61% in each county. L. geometricus (5%) had the third abundance. All of the specimens were female (100%). This spe- cies was more prevalent in mountainous roads Iranian J Arthropod-Borne Dis, (2007), 1(1): 52-57 J Rafinejad et al.: Systematic, Bioecology and… 54 from Sabzevar to Bardeskan (54.54%) and less prevalent in Torbateheidarieh with 9.09%. L. pallidus had 1% abundance. One specimen was female and 2 of them were male (66.6%). All of the specimens were found in one burrow in the ground near the road of Torbateheidarieh to Gonabad. Considering the review on foreign and Iranian literatures on Iranian spiders, here is the first report on the occurrence of males of L. pal- lidus as well as both sexes of L. trdecimgottatus and L. geometricus in the country. Spider fe- males, mate only once in their life and 3-13 egg sacs could be laid by each spider. In each egg sac a total of 50-500 eggs may be seen. The time interval between each laying egg is estimated 15 d. The number of molting is 4-8 time, depending on species, and environ- mental condition. In nature, adult males die af- ter several months but females can live several months. In laboratory condition they can live up to 18 mo. Females have one generation in each year. Generations in each year are not signifi- cantly different in various species. The activi- ties of spiders initiate from May and continue until November. The peak of activity is in July, which is syn- chronized with wheat harvesting time. In con- clusion it should be emphasized that there is significant difference among species in terms of morphology, bioecology and life span. The sex ratio among collected specimens was 88% and 12% female and male, respectively. Cracks and crevices of mud walls that are traditionally con- structed around the farms and gardens in the study area are the main shelters for hiding, breed- ing and egg laying of spiders. Furthermore the summer provides the most suitable and favor- able climatic condition for the activities of these spiders when 52.8% of spiders were collected in this season. All the reported cases were checked in terms of their sex, age, occupational, geographi- cal distribution and seasonal biting clinical mani- festation. During the investigation 195 cases of biting were studied com-posing of 70.8 % male and 29.2% female. The most prevalence cases were observed in middle age (20-55 yr old) and particularly among farmers (36.4%). Table 1 shows the percentage of species in whole study area. Seasonal activity of spiders has shown in Table 2. Prevalence of widow spi- ders and egg sac collected from natural habitat in north and central of Khorasan Province, 1995-97 are presented in Table 3. Severe cases are hallmarked by difficulty in breathing and unconsciousness, which may lead to death due to asphyxia preceded by convul- sions. Study showed that all of the people biting with spiders have 1 to 8 d hospitalization. Dur- ing the investigation duration a total cases of 195 bites were studied composing of 70.8 % male and 29.2% female. The most prevalence cases were observed in midge (20-55 yr old). Biting were more prevalent particularly among farmers (36.4%), then house women (27.9%), students (16.4%), animal husbandman (9.7%), workers (6.7%) and etc (3%). Most of the pa- tients had localized pain, pain in one organ and distributed pain. Victims experience abdominal cramps and abdominal cramps (36%), itching (34%) nausea (31.4%), eurhythmy (24%), edema in eye-lids (17.8%), tachycardia (11%) and mus- cle cramps (10.3%). Among different cities, Mashad had (60%) the most reported cases in the study area. After Mashad, Neishabour had 9.1% of cases, Chenaran 9.1%, and another part of the counties had 15.8% cases. Among differ- ent parts of the body, foot (47%) was more in- jured than the other parts of the body, followed by hands (28%), trunk (14%) and head and neck (11%). Seventeen percent of victims were baited outdoors and 83 percent were baited in- doors. Summer was the peak of biting which is synchronized by spider activity. 96.5% of pa- tients exhibited localized pain from which only 2% had no pain in the bitten part and 87% had a generalized pain in whole body. Hospitalization time of patients was 1-8 d. The peak of case re- ports were in 1995, whereas no any cases were found during 1998-2000. Iranian J Arthropod-Borne Dis, (2007), 1(1): 52-57 J Rafinejad et al.: Systematic, Bioecology and… 55 Fig. 1. Mashahad County (study area) Table 1. Prevalence of adult widow spiders collected from north and central of Khorasan Province according to sex and species, 1995-97. Species Male Female Sum No. % No. % No. % L. tredecimguttatus 17 7.87 117 54.17 134 62.04 L. dahli 6 2.78 62 28.70 68 31.48 L. geometricus 0 0 11 5.09 11 5.09 L. pallidus 2 0.93 1 0.46 3 1.39 Total 25 11.57 191 88.43 216 100 Table 2. Prevalence of widow spiders collected from north and central of Khorasan Province according to season and year Year/Season Spring Summer Autumn Total No. % No. % No. % No. % 1995 24 11.11 82 37.96 8 3.7 114 52.78 1996 24 11.11 42 19.4 13 6.01 79 36.57 1997 6 2.8 17 7.9 0 0 23 10.65 Total 54 25 114 52.8 21 9.71 216 100 Table 3. Percentage of widow spiders and egg sac collected from natural habitat in north and central of Khorasan Province during study period Natural habitat Adult Egg sac No. % No. % Under or in split of stones 51 23.6 71 27.5 Around the farm and gardens 45 20.8 92 35.66 Cracks and crevices of mud walls 37 17.13 49 18.99 Rodent holes 35 16.2 19 7.36 Vegetation, trees and hedgerow 29 13.43 15 5.81 Ground holes 19 8.8 12 4.65 Total 216 100 258 100 Iranian J Arthropod-Borne Dis, (2007), 1(1): 52-57 J Rafinejad et al.: Systematic, Bioecology and… 56 DISCUSSION Although most species of spiders are ven- omous, only ten or so are able to induce human envenomations (Dzelalija and Medic 2003). The black widows importance is directly related to its reputation as a poisonous spider (Nicholson and Graudins 2002), however, bites are uncom- mon and serious long-term complications or death is rare (Landeka and Plenkovic 2003). A comprehensive study was carried out during 1995-97 in northern part of Iran for the study of distribution, biology, ecology and systematic of widow spiders. A total of 216 adult spiders and 258 egg sac were collected form the study areas. The identified species were L. tredecimgottatus (62%), L. dahli (32%), L. geometricus (5%) and L. pallidus (1%). The sex ratio among collected specimens was 88% and 12% female and male, respectively. Female spiders, mate only once in their life and 3-13 egg sacs could be laid by each spider. In each egg sac a total of 50-500 eggs may be seen. The time interval between each laying egg is estimated 15 d. The number of molting is 4-8 time depending on species, and environmental condition. In nature, adult males die after sev- eral months but females can live several months. In laboratory condition they can live up to 18 mo. Females have one generation in each year. Generations in each year have not signifi- cant difference in different species. The activi- ties of spiders initiate from May and continue until November. The peak of activities is in July, which is synchronized with wheat harvesting time. Biting were more prevalent particularly among farmers and house women. Because of farming, among different parts of the body, feet and hands were more injured than the other parts of the body (no need to repeat the results). From table 1 it can be concluded that among spiders collected from study areas the species L. tredecimgottatus exhibit the more prevalence in the region, whereas the species L. geometricus had the lowest prevalence. The spiders were more seasonal activity dur- ing summer, 1995 and less seasonal activity was seen in autumn 1997. In natural habitat spi- ders have more prevalent under or in split of stones and have less prevalent in ground holes. In the field studies it is concluded that species of Latrodectus genus have different morphol- ogic and ecology and species identification with- out its bioecology is very difficult. Also more studies are needed to highlight the taxonomic situation of the species of the spider widows in other parts of country. Trash, lumber piles, bricks, weeds, and outside structures are good breeding places for spiders and should be cleaned up. Inside the home spider webs should be brushed down. The egg sacs should be destroyed to prevent hundreds of young spiders from emerg- ing. Vacuum cleaner attachments may be used to clean walls, and the collected debris should be destroyed. Another recommenddation is envi- ronmental sanitation, quarantine, chemical con- trol including residual spraying and biological control (Landeka and Plenkovic 2003). Control efforts should target black widow spider webs because that is where the spider spends most of its time. Control is best achieved by following an integrated pest management (IPM) strategy, which involves using multiple approaches such as preventive measures, exclusion, sanitation, and chemical treatment when necessary (Landeka and Plenkovic 2003). IPM requires a thorough inspection of the building to locate the pest. An inspection preferably should be done at night because the black widow spider is nocturnal (Landeka and Plenkovic 2003). All of the clini- cal symptoms might not be present. The bite of a black widow spider initially may go unno- ticed, but some people report a short stabbing pain. The venom is neurotoxic, affecting the hu- man nervous system. At first, there may be slight local swelling and two faint red spots, which are puncture points from the fangs. The physical reaction to a spider bite depends on the amount of venom injected and an individual's sensitivity including age and sensitivity to venom. Small children most severely affected (Landeka and Plenkovic, 2003). Iranian J Arthropod-Borne Dis, (2007), 1(1): 52-57 J Rafinejad et al.: Systematic, Bioecology and… 57 The present studies show that widow spider bit- ing is an important problem in the study areas, which periodically appear every several years. In conclusion it should be emphasized that spi- der bite is an important health problem in the region. For combating the problem health edu- cation for both local authorities as well as com- munity is essential. ACKNOWLEDGEMENTS The authors would like to appreciate very much from Mr Afshar, Dr Balali and their colleagues in Health Center of Khorasan Province to help us to carry out the research and also to the staff of School of Public Health and Institute of Health Research, Medical Sciences/ Tehran Uni- versity for their kind collaboration. This re- search was financially supported by the School of Public Health, Medical Sciences/Tehran Uni- versity. 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