Effect of washing on the bioefficacy of insecticide-treated nets (ITNs) and long-lasting insecticidal nets (LLINs) against main malaria vector Anopheles stephensi by three bioassay methods

Background & objectives: The use of pyrethoid impregnated bednets is one of the main malaria vector control strategies worldwide. The objective of the present study was to evaluate the bioefficacy of bednets impregnated with various pyrethroids after repeated washings. Methods: The effectiveness of bednets impregnated with permethrin, deltamethrin, bifenthrin, etofenprox and long-lasting bednets like OlysetNet® and PermaNet® which were provided by WHOPES was evaluated. The tests were carried out according to the WHO-recommended methods. Malaria vector, Anopheles stephensi was exposed to impregnated bednets for 3 min and the mortality was measured after 24 h recovery period. Knockdown was measured as well.Results: Results of three methods of bioassay tests showed that between two LLINs, PermaNet® was more efficient than OlysetNet®. Results of ITNs exhibited that deltamethrin and permethrin were more effective than etofenprox and bifenthrin as impregnants.Interpretation & conclusion: Findings of this study will be useful for WHO, local authorities and people who wish to use different pyrethroid-impregnated bednets for malaria vector control

The effect of repeated washing of long-lasting insecticide-treated nets (LLINs) on the feeding success and survival rates of Anopheles gambiae

<p>Abstract</p> <p>Background</p> <p>Insecticide-treated nets protect users from mosquito bites, thereby preventing transmissions of mosquito borne pathogens. Repeated washing of nets removes insecticide on the netting rendering them ineffective within a short period. Long-lasting insecticide-treated nets (LLINs) offer longer time protection against such bites because they are more wash resistant, and are preferred to conventionally treated nets. However, there is limited information on the effect of repeated washing of LLINs on the feeding success and survival of wild malaria vectors.</p> <p>Methods</p> <p>The current study evaluated the effect of repeated washing of four brands of LLINs on the feeding success and survival rates of <it>Anopheles gambiae </it>sl reared from wild strains. In this study, two- to five-day old F1s, reared from gravid mosquitoes collected from an area with a high coverage of LLINs were offered blood meals through protective barriers of the above LLINs. Mosquitoes were exposed for a period of 10 minutes each time. Nets were tested unwashed and subsequently after every 5^ththrough wash 15. After exposure mosquitoes were sorted out according to their feeding status. They were then held under normal laboratory conditions for 24 hours and mortality was scored in both fed and unfed.</p> <p>Results</p> <p>It was observed that mosquitoes did not feed through a barrier of unwashed LLINs. However, the feeding success and survival rates increased with successive number of washes and were also net brand dependant. After 15 washes, 49% of vectors succeeded to feed through a protective barrier of PermaNet 2.0 and 50% of the fed died after 24 hrs while after the same number of washes 60% of vectors succeeded to feed through Olyset brand of LLINs and all of them survived. In general, more mosquitoes survived after feeding through Olyset compared to the other four brands that were evaluated. When efficacy of individual LLINs was compared by a t-test analysis to a conventionally treated net, the results were not significantly different statistically for Olyset (<it>p = </it>0.239) and NetProtect (TNT) (<it>p = </it>0.135). However, the results were highly significant when comparison was made with PermaNet and Interceptor (BASF); <it>p </it>values 0.015 and 0.025 respectively.</p> <p>Conclusion</p> <p>The result of this study shows that repeated washing of LLINs at short time intervals using local washing methods may render them infective within a short time in preventing local vectors from feeding.</p

Comparison of the efficacy of long-lasting insecticidal nets PermaNet® 2.0 and Olyset® against Anopheles albimanus under laboratory conditions

Insecticide-treated nets provide a reduction in human-vector contact through physical barrier, mortality and/or repellent effects that protect both users and non-users, thereby protecting the wider community from vector-borne diseases like malaria. Long-lasting insecticide-treated nets (LLINs) are the best alternative. This study evaluated the bioefficacy of LLINs PermaNet® 2.0 and Olyset® under laboratory conditions with Anopheles albimanus. The laboratory strain was evaluated for insecticide susceptibility with selected insecticides used for malarial control. Regeneration time and wash resistance were evaluated with the standard bioassay cone technique following WHO guidelines. Heat assistance was used for Olyset® nets; the nets were exposed to four different temperatures to speed the regeneration process. The regeneration study of PermaNet® 2.0 showed that efficacy was fully recovered by 24 h after one and three washes and wash resistance persisted for 15 washes. Regeneration of Olyset® nets was not observed for nets washed three times, even with the different temperature exposures for up to seven days. Thus, for Olyset® the wash resistance evaluation could not proceed. Differences in response between the two LLINs may be associated with differences in manufacturing procedures and species response to the evaluated LLINs. PermaNet® 2.0 showed higher and continuous efficacy against An. albimanus

House Dust Mite Contamination in Hotels and Inns in Bandar Abbas, South of Iran

House dust mites have been shown to be strongly associated with allergic respiratory diseases such as,bronchial asthma, rhinitis and atopic dermatitis in the world. The climatic conditions of Bandar-Abbas, which is located in a coastal area and has a humid subtropical climate, provide a suitable place to proliferate mites. The aim of this study was to determine the contamination rate and analyze the house dust mite fauna in hotels and inns in Bandar-Abbas that had not been investigated previously. In this study 6 hotels and 6 inns were selected randomly in six areas of Bandar-Abbas. Two dust samples were collected from each place with a vacuum cleaner. One square meter of carpets and mattresses were vacuumed for a period of 1 min. Then the samples were cleared in lactic acid and then mites were mounted in Hoyer&apos;s medium for study and identification. A total of 2644 mites were collected and identified. The major mite family was Pyroglyphidae (98%). Dermatophagoides pteronyssinus   was the most frequent and most numerous species recorded, occurring in 91% of samples examined and forming 88% of the Pyroglyphidae and 86% of the total mite populations. The family Cheyletidae was less commonly found with Cheyletus malaccensis   (2%). Most of the mites were isolated from the carpets (57.5%), and a smaller number from mattresses (42.5%). Mites were present in 96% of the dust samples. Results revealed that all inns and 83% of hotels were contaminated by more than one species of mite and 34% of them had a population of more than 100 mites /g dust. This rate of contamination can be a major risk factor in asthma and other respiratory allergic diseases

Arthropod Parasites of Rodents in Khorram Abbad district, Lorestan Provincen of Iran

Ectoparasites are considered as the main vectors of zoonotic diseases. They play an important role for transmission of wide variety of diseases such as CCHF, leishmaniosis and plague to human and vertebrates. Mammals, especially rodents, are the most important reservoirs of zoonotic diseases. The aim of this study was to identify the ectoparasites of rodents captured in Korram-Abad, Lurestan Province, Iran during year 2002-2003. Rodents were live trapped from 24 localities in six major land-resource areas. A total of 167 alive rodent specimens were transported to the laboratory and after anesthetizing by chloroform their ectoparasites were removed. Collected ectoparasites were mounted and identified. Altogether 218 ectoparasites related to 3 orders, 6 families, 6 genera, and 7 species were systematically recognized. Fleas with 3 species had the most number of species, mites and lice allocated the most (64.67%) and the least (3.21%) frequency of ectoparasites, respectively. Ectoparasites were more prevalent in Zagheh area (38.99%). Haemolaelaps glasgowi (42.2%) was the most common ectoparasite while, Nosopsyllus irranus only constituted approximately 0.91% of specimens. Zagheh area could be a high-risk zone for zoonotic disease transmission due to poor hygienic circumstance

REGIONAL EVALUATION OF BACTERIAL CONTAMINATION IN HOSPITAL ENVIRONMENT COCKROACHES

Cockroaches play an important role in transmission of different diseases either mechanically and occasionally biologically. The aim of current study was on the identification of cockroaches and their contamination to different bacteria in two hospitals affiliated to the Kordestan University of Medical Sciences which was performed in 2003. Cockroaches were collected from different parts using sticky traps, direct collection, and by means of vacuum cleaner. Collected cockroaches were identified according to the reliable systematic keys. Some of the collected cockroaches were selected randomly for the presence of bacteria in their external parts as well as in the digestive tract using specific culture media. Totally 450 specimens were collected. From which 44.4% identified as American Cockroach, Periplaneta Americana   and remaining German cockroach, Blattella germanica   . Among collected cockroaches 58 specimens of German cockroaches and 40 American cockroaches were selected to search for the presence of bacteria. Results of culture media exhibited that 89.8% (88.98) of cockroaches were positive to the bacteria. The bacteria were found mainly on external parts (67%) and remaining from alimentary canal. The main common bacteria was found Escherichia coli   , however, only 5.1% was Escherichia sp., which was found on external parts. Among two hospitals it is found that Tohid hospital was more infected (97.5%). In the hospitals the infectivity of American cockroaches was more prevalent than other species. All the American cockroaches and 70% of German cockroaches were infected to at least one bacterium. Result showed that the presence of cockroaches in the hospitals can threaten the health of hospitalized patients. Both cosmopolitan species was found infected in the hospitals. Sanitation of different departments as well as different method of control is recommended in the context of Integrated Vector Management for cockroach control

The Occurrence of Red-Back Spider Latrodectus hasselti (Araneae: Theridiidae) in Bandar Abbas, Southern Port of Iran

Background:  Due to importance and fatal affect of Red-back spiders, Latrodectus hasselti, a faunistic survey for presence of this spider in Bandar Abbas has been conducted. This animal is considerably the most medically importance spiders all over the world. Methods: Live adult spider specimens were collected from Bandar Abbas town using hand catch conventional method and transferred to the laboratory throughout the summer of 2008. They  were identified based on mor­phological characteristics and taxonomic keys and confirmed by some external experts. Results: Results showed the occurrence of the red-back spider, L. hasselti from Bandar Abbas, southern port of Iran. Two female specimens were found. The spider had specific morphological characters  including black color with an obvious orange to red longitudinal strip on its upper parts of  abdomen. Conclusion: Although the specimens were collected from south of the country, however since the region is an important harbor and port and goods come form different parts of world we assume the possibility of arrival  from its origin and native breeding sites of the world. Therefore further investigation is needed to clarify the presence of this species in different parts of Iran.

Faunistic Study and Biodiversity of Scorpions in Qeshm Island (Persian Gulf)

 Background: Scorpions are known as the most widespread poisonous creatures that cause casualties and death to human. They are distributed in tropical and subtropical areas. Among the sixteen Iranian Island in the Persian Gulf, Qeshm Island is the biggest and is located in the focus of the important internal and international commercial marinelines. Furthermore, thousands of tourists also visit the Island every year for its natural beauties and the siteseeings. The present research study was carried out during 1998-99 throughout Qeshm Island in order to know the species of scorpions, their abundance, the distribution and control strategy in order to reduce the scorpion stings and to safeguard the visitors as well as the local population. Methods: Collections were made randomly during the night. Samples were searched by black light and then collected by forceps. A total of 102 scorpions were captured. Results: The scorpions were identified as Buthotus jayakari numbered 42 specimens (41.17%) and B. leptochelys numbering only 7 specimens (6.86%) belonging to the family Buthidae. Androctonus crassicauda was collected in the most parts of the Island and considered as the dominant species. The sex ratio was 1:1.53 in favor of females. B. lep­tochelys was rare species and by far restricted in its distribution. Conclusion: Considering the high population of A. crassicauda and its wide distribution, it is regarded to be re­sponsible for the majority of scorpion stings in Qeshm Island

Human myiasis survey in Ilam Province, Southwest of Iran

Myiasis is the infestation of live human and vertebrate animals with dipterous larvae, which at least for a period. Ilam Province of Iran is one of the most important animal husbandry areas, especially nomadic, in Iran. The objective of this study was to identify the prevalence of myiasis in shepherds in Ilam Province. A cross-sectional study was conducted among the shepherds in Ilam Province, western Iran. Out of the 11 counties in Ilam Province, 6 were randomly chosen from three different climates for this study. A questionnaire was used by a trained interviewer to obtain the information from subjects. The disease has been seen in spring, summer, and autumn seasons. About 94.1 of people have been infested at least once. Pharyngeal myiasis had the highest prevalence with 58.3. Itchy, painful throat, sneeze, cough, and headache were common symptoms. About 85.1 of people described the symptoms of the disease as severe and very severe. About 75.4 stated that the duration of the disease was more than 5 days. According to the results of the study, it was found that the prevalence of myiasis among shepherds in the Ilam Province is high and it is necessary to take appropriate measures to control the disease and increase health literacy