Biodiversity of mosquitoes and Mansonia uniformis as a potential vector of Wuchereria bancrofti in Hulu Sungai Utara District, South Kalimantan, Indonesia

Effect of expanding farmlands with domestication of animals in the vicinity of disturbed swamps and built-up farmland ponds on population dispersion and decline of locally adapted Mansonia vectors (Diptera: Culicidae)

Background and Objectives

The adaptive processes and resilience of Mansonia vectors responsible for bioindicators can change in response to climate, land use, and environmental changes. This study evaluated the effects of expanding farmlands with the domestication of animals in the vicinity of either disturbed swamps or built-up farmland ponds on the population dispersion and decline of locally adapted Mansonia faunas as a result of expanding farmlands in Thailand.

Materials and Methods

Based on environmental surveys, four different geographically defined study sites were selected: I - the expanding farmlands with domestication of livestock and pet animals in the vicinity of low-lying swamp with habitat fragmentation and aquatic vegetation; II - the expanding farmlands with domestication of pet animals in the vicinity of elevated swamp with habitat destruction and aquatic vegetation; III - the expanding farmlands with domestication of livestock and pet animals in the vicinity of low-lying farmland ponds with restoration and aquatic vegetation; and IV - the expanding farmlands with domestication of pet animals in the vicinity of elevated farmland ponds with restoration and aquatic vegetation. Human landing catch collection method was used to periodically assess the species composition and abundance of Mansonia vectors.

Results

Aggregated distributions and seasonal abundances of Mansonia faunas (Mansonia uniformis, Mansonia indiana, Mansonia annulifera, Mansonia annulata, Mansonia bonneae, and Mansonia dives) with variable proportions were observed at all the study sites. A decline in the population of Mansonia faunas, except for Ma. uniformis, was observed at study sites I and II.

Conclusion

The anticipated effects of expanding farmlands affected the population dispersion and decline of locally adapted Mansonia faunas, thus representing a diverse assemblage of Mansonia species with different adaptations, ecological tolerances, and host exploitation strategies in life. These effects depended either on the function of disturbed swamps or on the development of farmland ponds, whether they provided a wide range of freshwater habitats, or on the domestication of animals, whether they provided animal blood meal sources.

The impact of mosquito sampling strategies on molecular xenomonitoring prevalence for filariasis: a systematic review

Objective

To explore the impact of mosquito collection methods, sampling intensity and target genus on molecular xenomonitoring detection of parasites causing lymphatic filariasis.

Methods

We systematically searched five databases for studies that used two or more collection strategies for sampling wild mosquitoes, and employed molecular methods to assess the molecular xenomonitoring prevalence of parasites responsible for lymphatic filariasis. We performed generic inverse variance meta-analyses and explored sources of heterogeneity using subgroup analyses. We assessed methodological quality and certainty of evidence.

Findings

We identified 25 eligible studies, with 172 083 mosquitoes analysed. We observed significantly higher molecular xenomonitoring prevalence with collection methods that target bloodfed mosquitoes compared to methods that target unfed mosquitoes (prevalence ratio: 3.53; 95% confidence interval, CI: 1.52-8.24), but no significant difference compared with gravid collection methods (prevalence ratio: 1.54; 95% CI: 0.46-5.16). Regarding genus, we observed significantly higher molecular xenomonitoring prevalence for anopheline mosquitoes compared to culicine mosquitoes in areas where Anopheles species are the primary vector (prevalence ratio: 6.91; 95% CI: 1.73-27.52). One study provided evidence that reducing the number of sampling sites did not significantly affect molecular xenomonitoring prevalence. Evidence of differences in molecular xenomonitoring prevalence between sampling strategies was considered to be of low certainty, due partly to inherent limitations of observational studies that were not explicitly designed for these comparisons.

Conclusion

The choice of sampling strategy can significantly affect molecular xenomonitoring results. Further research is needed to inform the optimum strategy in light of logistical constraints and epidemiological contexts.

Bacterial diversity on larval and female Mansonia spp. from different localities of Porto Velho, Rondonia, Brazil

Studies based on the bacterial diversity present in Mansonia spp. are limited; therefore, the aim of this study was to investigate the bacterial diversity in females and larvae of Mansonia spp., describe the differences between the groups identified, and compare the microbiota of larvae from different collection sites. Sequences of the 16S rRNA region from the larvae and females of Mansonia spp. were analyzed. Diversity analyzes were performed to verify the possible bacterial differences between the groups and the collection sites. The results showed Pseudomonas was the most abundant genus in both females and larvae, followed by Wolbachia in females and Rikenellaceae and Desulfovibrio in larvae. Desulfovibrio and Sulfurospirillum, sulfate- and sulfur-reducing bacteria, respectively, were abundant on the larvae. Aminomonas, an amino acid-degrading bacterium, was found only in larvae, whereas Rickettsia was identified in females. Bacterial diversity was observed between females and larvae of Mansonia and between larvae from different collection sites. In addition, the results suggest that the environment influenced bacterial diversity.

Emergence of zoonotic Brugia pahangi parasite in Thailand

Zoonotic Brugia pahangi parasite infections in humans have emerged over two decades in Southeast Asia (SEA), including Malaysia and Thailand. The species is commonly found in domestic cats and dogs as the natural reservoir hosts. The sporadic transmission pattern of B. pahangi zoonosis causes childhood infections in Thailand and adulthood infections in Malaysia. It is crucial to understand the vulnerability in how zoonotic B. pahangi parasite is transmitted to susceptible persons in receptive settings and the exposure to the infection under impoverished environment to which the human-vector-animal interactions are related. This acquisition of knowledge will help multiple health science professions to apply One Health approach to strengthening the capacity in diagnosis and surveillance, and hence detecting and monitoring the "lingering" zoonotic B. pahangi infections present in vulnerable populations in Thailand and elsewhere in SEA. In this review article, the authors focused on articulating the concepts of plantation-related zoonotic B. pahangi filariasis by updating current knowledge of B. pahangi life cycle, vector's life cycle and current state of research on the epidemiology and ecology of B. pahangi zoonosis.

Surveillance Studies Reveal Diverse and Potentially Pathogenic-Incriminated Vector Mosquito Species across Major Botswana Touristic Hotspots

Vector mosquitoes contribute significantly to the global burden of diseases in humans, livestock and wildlife. As such, the spatial distribution and abundance of mosquito species and their surveillance cannot be ignored. Here, we surveyed mosquito species across major tourism hotspots in semi-arid Botswana, including, for the first time, the Central Kalahari Game Reserve. Our results reported several mosquito species across seven genera, belonging to Aedes, Anopheles, Culex, Mansonia, Mimomyia, Coquillettidia and Uranotaenia. These results document a significant species inventory that may inform early warning vector-borne disease control systems and likely help manage the risk of emerging and re-emerging mosquito-borne infections.