Anopheles subpictus carry human malaria parasites in an urban area of Western India and may facilitate perennial malaria transmission

Abstract

BackgroundIndia contributes 1.5–2 million annual confirmed cases of malaria. Since both parasites and vectors are evolving rapidly, updated information on parasite prevalence in mosquitoes is important for vector management and disease control. Possible new vector-parasite interactions in Goa, India were tested.MethodsA total of 1036 CDC traps were placed at four malaria endemic foci in Goa, India from May 2013 to April 2015. These captured 23,782 mosquitoes, of which there were 1375 female anopheline specimens with ten species identified using morphological keys. Mosquito DNA was analysed for human and bovine blood as well as for Plasmodium falciparum and Plasmodium vivax infection.ResultsHuman host feeding was confirmed in Anopheles stephensi (30 %), Anopheles subpictus (27 %), Anopheles jamesii (22 %), Anopheles annularis (26 %), and Anopheles nigerrimus (16 %). In contrast, Anopheles vagus, Anopheles barbirostris, Anopheles tessellates, Anopheles umbrosus and Anopheles karwari specimens were negative for human blood. Importantly, An. subpictus, which was considered a non-vector in Goa and Western India, was found to be a dominant vector in terms of both total number of mosquitoes collected as well as Plasmodium carriage. Plasmodium infections were detected in 14 An. subpictus (2.8 %), while the traditional vector, An. stephensi, showed seven total infections, two of which were in the salivary glands. Of the 14 An. subpictus infections, nested PCR demonstrated three Plasmodium infections in the salivary glands: one P. vivax and two mixed infections of P. falciparum and P. vivax. In addition, ten gut infections (one P. vivax, six P. falciparum and three mixed infections) were seen in An. subpictus. Longitudinal mosquito collections pointed to a bimodal annual appearance of An. subpictus to maintain a perennial malaria transmission cycle of both P. vivax and P. falciparum in Goa.

Malaria in North-East India: Importance and Implications in the Era of Elimination

“…An. subpictus incriminated as a major malaria vector in Western India [95] has been identified in mosquito epidemiology studies in Mizoram [96]. Substantial focus has to be given to understanding the emergence of new vectors and vector parasite relationships for formulating effective vector-control strategies in this region.…”

Demographic and clinical profiles of Plasmodium falciparum and Plasmodium vivax patients at a tertiary care centre in southwestern India

“…While the year-round presence of P. vivax cases may be explained by the ability of P. vivax parasites to lie dormant as hypnozoites in liver stages with small numbers re-emerging during the dry season, this would not be the case for P. falciparum [8, 45]. Although it remains to be established, a more perennial transmission cycle of both P. vivax and P. falciparum may be aided by the recent discovery of a previously unsuspected vector in this region, Anopheles subpictus [46]. This vector has been shown to peak in numbers and transmission capacity both after the monsoons when the traditional urban malaria vector Anopheles stephensi peaks, but also in the dry season when An.…”

Studi Bioekologi Vektor Malaria di Daerah (Yang Mendapat Sertifikat) Eliminasi Malaria di Kabupaten Jembrana, Bengkalis dan Bulukumba

“…Meskipun kabupaten ini juga telah mendapatkan sertifikat eliminasi, namun hasil ini mengindikasikan bahwa di ekosistem baik hutan, non hutan maupun pantai masih berpotensi terjadi penularan malaria kembali. 25,26 Beberapa faktor yang mempengaruhi transmisi patogen antara lain faktor biologi dan faktor lingkungan. Salah satu faktor biologi adalah keberadaan vektor dan ketahanan nyamuk terhadap patogen.…”