Molecular characterization, biological forms and sporozoite rate of Anopheles stephensi in southern Iran

Objective: To identify the biological forms, sporozoite rate and molecular characterization of the Anopheles stephensi (An. stephensi) in Hormozgan and Sistan-Baluchistan provinces, the most important malarious areas in Iran. Methods: Wild live An. stephensi samples were collected from different malarious areas in southern Iran. The biological forms were identified based on number of egg-ridges. Molecular characterization of biological forms was verified by analysis of the mitochondrial cytochrome oxidase subunit I and II (mtDNA-COI/COII). The Plasmodium infection was examined in the wild female specimens by species-specific nested–PCR method. Results: Results showed that all three biological forms including mysorensis, intermediate and type are present in the study areas. Molecular investigations revealed no genetic variation between mtDNA COI/COII sequences of the biological forms and no Plasmodium parasites was detected in the collected mosquito samples. Conclusions:Presence of three biological forms with identical sequences showed that the known biological forms belong to a single taxon and the various vectorial capacities reported for these forms are more likely corresponded to other epidemiological factors than to the morphotype of the populations. Lack of malaria parasite infection in An. stephensi, the most important vector of malaria, may be partly due to the success and achievement of ongoing active malaria control program in the region.

Bioassay evaluation on the efficacy of α-cypermethrin impregnated into long lasting insecticide treated nets using Anopheles stephensi

OBJECTIVE@#To evaluate the bioefficacy of α-cypermethrin impregnated into long lasting insecticide treated nets (LLITNs-INTERCEPTOR®) against main malaria vector, Anopheles stephensi (An. stephensi).@*METHODS@#The effectiveness of bed net impregnated with α-cypermethrin (INTERCEPTOR®) with washing was evaluated. The washing procedure and bioassay tests were carried out according to the WHO-recommended methods. Malaria vector, An. stephensi was exposed to impregnated bed net for three minutes and then mortality measured after 24 h recovery period. Knockdown was also measured according to the logarithmic times.@*RESULTS@#Result of cone bioassay method showed that bioefficacy of α-cypermethrin decreased from 100% in unwashed to 15% in 20 washes. KT(50) was measure as one minute in one wash and increased to 40 min in 20 washes.@*DISCUSSION@#Findings of this study provide guideline for malaria vector control authorities and people using pyrethroid-impregnated bed nets.

Demonstration of malaria situation analysis, stratification and planning in Minab District, southern Iran

OBJECTIVE@#To demonstrate malaria situation analysis, stratification and planning for an endemic area in southern Iran.@*METHODS@#Data on health system, population, meteorological parameters, malaria cases, anopheline vectors, and control activities during 2005-2007 was obtained from Minab Health Center, Minab Meteorological Station and published documents about malaria elements in the study area. A datasheet was created in excel 2003 for analysis.@*RESULTS@#There were 644 health staff working in Minab District including 99 health staff in malaria control program. The health facilities are distributed as follow: 1 hospital with 96 beds, 23 health centers including private centers (10 in Minab city and 13 in rural area of Minab District) and 119 health houses in rural areas of Minab District. A nopheles stephensi was the dominant species in Minab District, however, Anopheles dthali, Anopheles superpictus, Anopheles fluviatilis, Anopheles multicolor, Anopheles pulcherrimus and Anopheles turkhudi can also be found in the area. Anopheles stephensi was reported susceptible to malathion, propoxur, primphos-methyl, lambda-cyhalothrin permethrin and deltamethrin, and resistant to DDT and dieldrin in the area. During the study period a total of 10 665 positive cases were reported, mainly due to local transmission (99.6%). Plasmodium vivax was the main causative agent followed by Plasmodium falciparum. There were reports about drug resistance of Plasmodium falciparum in the area.@*CONCLUSIONS@#Using different parameters, Minab was classified into 3 strata. A plan was designed based on described goal, objectives and targets. The approaches of this plan were categorized into: health education, early detection and correct treatment, and vector control. Main constraints of these approaches are population movement between Iran, Pakistan and Afghanistan; vector control challenges at district, inadequate skilled medical staff in malaria case management and weak inter-sectorial coordination for malaria control, especially in urban areas.

Detection of mixed Plasmodium falciparum & P. vivax infections by nested-PCR in Pakistan, Iran & Afghanistan.

Background & objectives: Species identification and information on transmission pattern of malaria parasite in any malaria endemic area is key to success for a malaria control programme. In this investigation, malaria diagnosis using molecular method was used to assess the transmission pattern of malaria parasite in three malaria endemic regions: Afghanistan, Iran and Pakistan. Methods: Blood samples were collected from the patients presenting with vivax malaria from Afghanistan (n = 108), Iran (n = 200) and Pakistan (n = 199). Malaria parasite detection was made by the gold standard (microscopy) and also nested-PCR assay, using 18S small sub-unit ribosomal RNA (ssrRNA) gene. Results: Based on microscopy method, the level of mixed infection was zero to 2.5 per cent; however, nested-PCR assay detected 6.5, 22 and 23.5 per cent mixed infections in samples collected from Afghanistan, Iran and Pakistan, respectively. The present results showed that the co-infection of P. vivax with P. falciparum was frequent in malaria endemic regions of Iran and Pakistan. Interpretation & conclusion: The present data suggest the need for improving microscopy diagnosis method and the clinician should also have careful clinical observation, along with the reports on Giemsa-stained thick blood films, particularly in summer time when P. vivax is predominant. Also sharing information on transmission pattern of mixed infection among these countries may help in designing better control strategies for malaria.