Abstract:Surveys of Anopheles mosquitoes were conducted in urban, rural, and natural areas of Tajikistan to obtain updated information on their distributions, especially in southern districts of the country where malaria is a prevalent disease. Nine species of Anopheles are found in Tajikistan. Anopheles superpictus, An. claviger, An. hyrcanus, and An. pulcherrimus are the most widespread and abundant species. Investigations in northern Tajikistan confirmed the presence of An. artemievi and the absence of An. martinius… Show more
BackgroundThe burden of malaria infection in the modern world remains significant. Specific changes in the relative proportions of malaria vector mosquitoes, Maculipennis Complex species, in the south of Western Siberia over the past 25 years of the 20th century have attracted wide attention as an indicator of their dynamic geographical distribution. In Eurasia, studies of fluctuations in the borders of areas occupied by sibling species of this complex, as well as their relative proportions in the areas where they are sympatric are epidemiologically important.MethodsSpecies identity and chromosomal polymorphisms within each population were defined by cytogenetic analysis of polytene chromosomes of third- and fourth-instar larvae and adult females of Anopheles mosquitoes collected over the period from 1973 to 2012. A total of 37 Anopheles samples (3,757 specimens) from the Ukraine, European Russia and the Urals were studied. To identify An. messeae s.l. cryptic species A and B, polymerase chain reaction and restriction fragment length polymorphisms of the second internal transcribed spacer rRNA genes sequences (ITS2 PCR-RFLP) were used.ResultsAn. maculipennis s.s. is expanding to the northeast at a speed of approximately 30 km per year. In 2008 or 2009, this species appeared in the Southern Urals. The emergence of An. maculipennis in this region was accompanied by a decrease in the proportions of An. messeae A and An. beklemishevi and by an increase in the proportion of An. messeae B within An. messeae s.l. It is highly likely that the southwestern border of An. beklemishevi distribution area could shift in the same direction as expanding area of An. maculipennis.ConclusionsThe geographical distribution of the Palaearctic mosquito species of the Maculipennis Complex is undergoing a gradual shift. Changes detected in the species distribution can be considered as a component of the biocenotic process triggered by global warming. Both the warming itself and consequent expansion of An. maculipennis s.s. to the northeast, followed by changes in the species composition of Anopheles as well as their relative proportions and fluctuations in the species areas, exacerbate the epidemiology of malaria infection in Eurasia.
BackgroundThe burden of malaria infection in the modern world remains significant. Specific changes in the relative proportions of malaria vector mosquitoes, Maculipennis Complex species, in the south of Western Siberia over the past 25 years of the 20th century have attracted wide attention as an indicator of their dynamic geographical distribution. In Eurasia, studies of fluctuations in the borders of areas occupied by sibling species of this complex, as well as their relative proportions in the areas where they are sympatric are epidemiologically important.MethodsSpecies identity and chromosomal polymorphisms within each population were defined by cytogenetic analysis of polytene chromosomes of third- and fourth-instar larvae and adult females of Anopheles mosquitoes collected over the period from 1973 to 2012. A total of 37 Anopheles samples (3,757 specimens) from the Ukraine, European Russia and the Urals were studied. To identify An. messeae s.l. cryptic species A and B, polymerase chain reaction and restriction fragment length polymorphisms of the second internal transcribed spacer rRNA genes sequences (ITS2 PCR-RFLP) were used.ResultsAn. maculipennis s.s. is expanding to the northeast at a speed of approximately 30 km per year. In 2008 or 2009, this species appeared in the Southern Urals. The emergence of An. maculipennis in this region was accompanied by a decrease in the proportions of An. messeae A and An. beklemishevi and by an increase in the proportion of An. messeae B within An. messeae s.l. It is highly likely that the southwestern border of An. beklemishevi distribution area could shift in the same direction as expanding area of An. maculipennis.ConclusionsThe geographical distribution of the Palaearctic mosquito species of the Maculipennis Complex is undergoing a gradual shift. Changes detected in the species distribution can be considered as a component of the biocenotic process triggered by global warming. Both the warming itself and consequent expansion of An. maculipennis s.s. to the northeast, followed by changes in the species composition of Anopheles as well as their relative proportions and fluctuations in the species areas, exacerbate the epidemiology of malaria infection in Eurasia.
“…pulcherrimus and An. hyrcanus populations which represent now the two main malaria vectors observed in the rice fields of Kunduz province [ 3 , 5 ] and in the wider region including the southern part of Tajikistan [ 6 ]. Due to its ability to survive at relatively high altitude, An.…”
BackgroundInsecticide resistance seriously threatens the efficacy of vector control interventions in malaria endemic countries. In Afghanistan, the status of insecticide resistance is largely unknown while distribution of long-lasting insecticidal nets has intensified in recent years. The main objective of this study was thus to measure the level of resistance to four classes of insecticides in provinces with medium to high risk of malaria transmission.MethodsAdult female mosquitoes were reared from larvae successively collected in the provinces of Nangarhar, Kunar, Badakhshan, Ghazni and Laghman from August to October 2014. WHO insecticide susceptibility tests were performed with DDT (4 %), malathion (5 %), bendiocarb (0.1 %), permethrin (0.75 %) and deltamethrin (0.05 %). In addition, the presence of kdr mutations was investigated in deltamethrin resistant and susceptible Anopheles stephensi mosquitoes collected in the eastern provinces of Nangarhar and Kunar.ResultsAnalyses of mortality rates revealed emerging resistance against all four classes of insecticides in the provinces located east and south of the Hindu Kush mountain range. Resistance is observed in both An. stephensi and Anopheles culicifacies, the two dominant malaria vectors in these provinces. Anopheles superpictus in the northern province of Badakhshan shows a different pattern of susceptibility with suspected resistance observed only for deltamethrin and bendiocarb. Genotype analysis of knock down resistance (kdr) mutations at the voltage-gated channel gene from An. stephensi mosquitoes shows the presence of the known resistant alleles L1014S and L1014F. However, a significant fraction of deltamethrin-resistant mosquitoes were homozygous for the 1014L wild type allele indicating that other mechanisms must be considered to account for the observed pyrethroid resistance.ConclusionsThis study confirms the importance of monitoring insecticide resistance for the development of an integrated vector management in Afghanistan. The validation of the kdr genotyping PCR assay applied to An. stephensi collected in Afghanistan paves the way for further studies into the mechanisms of insecticide resistance of malaria vectors in this region.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1149-1) contains supplementary material, which is available to authorized users.
“…Overall, the outcome of our research reported here and previously (Habirov et al 2012) should inform strategies for mosquito management and malaria prevention in Tajikistan. We anticipate that our Þndings will serve to guide decision makers in their development and implementation of local mosquito control programs.…”
Section: Resultsmentioning
confidence: 78%
“…Anopheles hyrcanus (Pallas), Anopheles pulcherrimus Theobald, and Anopheles superpictus Grassi (Diptera: Culicidae) were identiÞed as "potential" vectors during a recent appraisal of malaria in the rice-growing areas in the southwestern region of the country (Matthys et al 2008), and the last two species are assumed to be of greatest epidemiological importance in the far north of Tajikistan . However, of the nine Anopheles species that are known to occur in Tajikistan (Habirov et al 2012 (Kadamov and Khabirov 2009). Because Anopheles algeriensis Theobald, Anopheles barianensis James, Anopheles lindesayi Giles, and Anopheles marteri sogdianus Keshishian are uncommon, they have not been associated with malaria transmission (Bulichev et al 1982, Kadamov 2010, Kadamov and Zvantsov 2010, Karimov 2009, Keshishyan 1941, Montchadsky and Shtakelberg 1943.…”
Entomological surveys were conducted in the malaria-endemic southwestern region of Tajikistan to establish which species of Anopheles may be responsible for malaria transmission. The head-thorax portions of 2,213 wild-caught Anopheles females-Anopheles superpictus Grassi (n = 1,292), Anopheles pulcherrimus Theobald (n = 376), Anopheles hyrcanus (Pallas) (n = 544), and Anopheles claviger (Meigen) (Diptera: Culicidae) (n = 1)-were tested for the presence of Plasmodium sporozoites using enzyme-linked immunosorbent assays. Four females of An. superpictus (three captured when landing on humans and one resting indoors) and one female of An. hyrcanus (captured when landing on a human indoors) were positive for Plasmodium vivax (Haemosporida: Plasmodiidae) VK-210. The infected females of An. superpictus were captured in the Hamadoni and Yovon districts of the Khatlon province, and the single infected female of An. hyrcanus was captured in the Jilikul district of the Khatlon province.
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