Mitochondrial variation in subpopulations of Anopheles balabacensis Baisas in Sabah, Malaysia (Diptera: Culicidae).

Anopheles balabacensis, the primary vector of Plasmodium knowlesi in Sabah, Malaysia, is both zoophilic and anthropophilic, feeding on macaques as well as humans. It is the dominant Anopheles species found in Kudat Division where it is responsible for all the cases of P. knowlesi. However there is a paucity of basic biological and ecological information on this vector. We investigated the genetic variation of this species using the sequences of cox1 (1,383 bp) and cox2 (685 bp) to gain an insight into the population genetics and inter-population gene flow in Sabah. A total of 71 An. balabacensis were collected from seven districts constituting 14 subpopulations. A total of 17, 10 and 25 haplotypes were detected in the subpopulations respectively using the cox1, cox2 and the combined sequence. Some of the haplotypes were common among the subpopulations due to gene flow occurring between them. AMOVA showed that the genetic variation was high within subpopulations as compared to between subpopulations. Mantel test results showed that the variation between subpopulations was not due to the geographical distance between them. Furthermore, Tajima's D and Fu's Fs tests showed that An. balabacensis in Sabah is experiencing population expansion and growth. High gene flow between the subpopulations was indicated by the low genetic distance and high gene diversity in the cox1, cox2 and the combined sequence. However the population at Lipasu Lama appeared to be isolated possibly due to its higher altitude at 873 m above sea level

First detection of Babesia sp. in Bornean sun bear (Helarctos malayanus euryspilus Horsfield) in Sabah, Malaysia

The Bornean sun bear, a subspecies of the endangered Malayan sun bear, resides only on Borneo Island and little is known about diseases or parasites that may impact their health. In 2019, blood and ticks were collected from 46 captive bears held at the Bornean Sun Bear Conservation Centre in Sabah, Malaysia during annual health examinations in response to previous blood smear analysis that revealed presumptive haemoparasites in more than half the resident bears. Polymerase chain reaction detected a unique Babesia sp. in one of the bears. Disease surveillance of mosquitoes trapped along the outer perimeter of the bears’ outdoor enclosure did not reveal any malaria parasites. This research marks the first documented case in Bornean sun bears of both a Babesia sp. and the Ixodes tick Haemaphysalis nr koningsbergeri. More research on incriminating the vector and the effects of Babesia infection on the health of Bornean sun bears is needed. Due to the zoonotic nature of babesiosis, mitigative actions should be taken to protect any humans that work with or come into close contact with these captive bears or their enclosures

Betanodavirus infection in marine fish aquaculture in Malaysia

Betanodavirus is known to cause mass mortality in many marine aquaculture fish species. In this study, we detected the virus in four different marine aquaculture fish species in Malaysia. These included humpback grouper (Cromileptisaltivelis), brown marbled grouper (Epinephelusfuscoguttatus), Asian seabass (Latescalcarifer) and golden pompano (Trachinoltusblochii). Out of 246 fish specimens analyzed using RT-PCR, 60.98% detected infected by the virus. Histological pathological analysis showed extensive cell vacuolationin the brain and retina tissues of severely infected specimens. However, some of the fish specimens detected positive using RT-PCR did not exhibit cell vacoulation which indicate the carrier state of those specimens. The RT-PCR amplification method developed in this study was shown useful as biosecurity tool in monitoringBetanodavirus infection in aquaculture. Although the origin of Betanodavirus in Malaysia is difficult to ascertained, evidence showed that some infections may have been contributed by the importation of fish fingerlings form neighboring countries. Currently, effective treatment of the viral disease is still impossible hence strict biosecurity measures need to be carried out in order to control the spread of the virus in fish stocks. These can include enforcement of biosecurity check and quarantine of every batch of imported fish, the use of virus-free broodstocks in hatchery, and proper disposal of infected fish stocks. In addition, good aquaculture practices must be carried in aquaculture farms or fish nursery all the time

A protocol for a longitudinal, observational cohort study of infection and exposure to zoonotic and vector-borne diseases across a land-use gradient in Sabah, Malaysian Borneo: a socio-ecological systems approach.

Introduction. Landscape changes disrupt environmental, social and biological systems, altering pathogen spillover and transmission risks. This study aims to quantify the impact of specific land management practices on spillover and transmission rates of zoonotic and vector-borne diseases within Malaysian Borneo. This protocol describes a cohort study with integrated ecological sampling to assess how deforestation and agricultural practices impact pathogen flow from wildlife and vector populations to human infection and detection by health facilities. This will focus on malaria, dengue and emerging arboviruses (Chikungunya and Zika), vector-borne diseases with varying contributions of simian reservoirs within this setting. Methods. A prospective longitudinal observational cohort study will be established in communities residing or working within the vicinity of the Stability of Altered Forest Ecosystems (SAFE) Project, a landscape gradient within Malaysian Borneo encompassing different plantation and forest types. The primary outcome of this study will be transmission intensity of selected zoonotic and vector-borne diseases, as quantified by changes in pathogen-specific antibody levels. Exposure will be measured using paired population-based serological surveys conducted at the beginning and end of the two-year cohort study. Secondary outcomes will include the distribution and infection rates of Aedes and Anopheles mosquito vectors, human risk behaviours and clinical cases reported to health facilities. Longitudinal data on human behaviour, contact with wildlife and GPS tracking of mobility patterns will be collected throughout the study period. This will be integrated with entomological surveillance to monitor densities and pathogen infection rates of Aedes and Anopheles mosquitoes relative to land cover. Within surrounding health clinics, continuous health facility surveillance will be used to monitor reported infections and febrile illnesses. Models will be developed to assess spillover and transmission rates relative to specific land management practices and evaluate abilities of surveillance systems to capture these risks

Life table analysis of Anopheles balabacensis, the primary vector of Plasmodium knowlesi in Sabah, Malaysia

No abstract available

Detection of echinostomatid trematode eggs at the forest–oil palm interface in Sabah, Malaysia

In this study, we report the occurrence of echinostomatid eggs in feces of wildlife, domestic animals and humans frequenting the forest–oil palm plantation interface in the Kinabatangan (Sabah, Malaysia), and discuss potential implications for public health. Using microscopy, we detected echinostomatid eggs in six host species, including Asian palm civets (Paradoxurus hermaphroditus [13/18]), leopard cats (Prionailurus bengalensis [3/4]), long-tailed macaques (Macaca fascicularis [1/10]), domestic dogs [3/5] and cats [1/1], and humans [7/9]. Molecular analysis revealed a close genetic proximity of civet echinostomatids to Artyfechinostomum malayanum, a zoonotic parasite of public health relevance. The intermediate hosts for A. malayanum have been reported in at least 3 districts in Sabah, suggesting that all the necessary elements required for the completion of the parasite's life cycle are present. Our findings point at the presence of zoonotic trematodes in an area with high human–wildlife interaction and highlight the potential public and animal health concern of zoonotic trematode infection in the context of Southeast Asia's rapidly changing ecosystems