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Detection of Babesia spp. in Dogs and Their Ticks From Peninsular Malaysia: Emphasis on Babesia gibsoni and Babesia vogeli Infections in Rhipicephalus sanguineus sensu lato (Acari: Ixodidae)

Prakash BK, Low VL, Vinnie-Siow WY, Tan TK, Lim YA, Morvarid AR, et al.

J Med Entomol, 2018 Aug 29;55(5):1337-1340.
PMID: 29762747 DOI: 10.1093/jme/tjy072

Canine babesiosis is an emerging tick-borne disease with a worldwide distribution, including Malaysia. While the prevalence of Babesia has been documented from dogs in Malaysia, occurrence of Babesia has been relatively little studied in their tick vectors. Accordingly, a total of 240 dogs and 140 Rhipicephalus sanguineus sensu lato (s.l.) (Acari: Ixodidae) ticks from Malaysia were molecularly screened for the presence of Babesia protozoa in the present study. Babesia gibsoni was only detected in ticks (1.4%), whereas Babesia vogeli was detected in both ticks (1.4%) and dogs (2.1%). This study highlights the detection of B. gibsoni and B. vogeli for the first time, in both adult and nymphal stages of R. sanguineus s.l. in Malaysia, suggesting the potential role of this tick species in transmitting canine babesiosis.
Detection of Anaplasmataceae agents and co-infection with other tick-borne protozoa in dogs and Rhipicephalus sanguineus sensu lato ticks

Low VL, Prakash BK, Lim YA, Tan TK, Vinnie-Siow WY, Sofian-Azirun M, et al.

Exp Appl Acarol, 2018 Aug;75(4):429-435.
PMID: 30073430 DOI: 10.1007/s10493-018-0280-9

Anaplasmosis and ehrlichiosis are of serious health concern worldwide for animals and humans. In the present study, we report the occurrence of Anaplasma platys and Ehrlichia canis in dogs and Rhipicephalus sanguineus sensu lato (s.l.) ticks from Peninsular Malaysia using a nested polymerase chain reaction assay based on amplification of the 16S rRNA gene. Anaplasma platys was detected from dogs and ticks with prevalence rates of 3.3% (8/240) and 2.9% (4/140), respectively. On the other hand, 12.9% (31/240) of the dogs and 0.7% (1/140) of the ticks were tested positive for E. canis. Additionally, co-infections of A. platys and E. canis with Babesia or Hepatozoon protozoa were also noted in this study. Double infection (E. canis + B. gibsoni) was observed in tick, whereas triple infections (E. canis + A. platys + B. vogeli and E. canis + A. platys + H. canis) were found in dogs. This study represents the first evidence of A. platys DNA in R. sanguineus s.l. in Malaysia.
Fulltext First molecular genotyping of A302S mutation in the gamma aminobutyric acid (GABA) receptor in Aedes albopictus from Malaysia

Low VL, Vinnie-Siow WY, Lim Y AL, Tan TK, Leong CS, Chen CD, et al.

Trop Biomed, 2015 Sep;32(3):554-6.
PMID: 26695218 MyJurnal

Given the lack of molecular evidence in altered target-site insecticide resistance mechanism in Aedes albopictus (Skuse) worldwide, the present study aims to detect the presence of A302S mutation in the gene encoding the gamma aminobutyric acid receptor resistant to dieldrin (Rdl) in Ae. albopictus for the first time from its native range of South East Asia, namely Malaysia. World Health Organization (WHO) adult susceptibility bioassay indicated a relatively low level of dieldrin resistance (two-fold) in Ae. albopictus from Petaling Jaya, Selangor. However, PCR-RFLP and direct sequencing methods revealed the presence of the A302S mutation with the predomination of heterozygous genotype (40 out of 82 individuals), followed by the resistant genotype with 11 individuals. This study represents the first field evolved instance of A302S mutation in Malaysian insect species.
Integration of Microscopic, Serologic and Molecular Techniques for Detection of Filarial Parasites in Dogs in Malaysia

Vinnie-Siow WY, Tan TK, Low VL, Teoh YB, Prakash BK, Sivanandam S, et al.

Acta Parasitol, 2021 Nov 19.
PMID: 34797497 DOI: 10.1007/s11686-021-00490-5

PURPOSE: Canine filariosis in domestic dogs caused by several species of filarids is an emerging vector-borne disease and the spread of this disease remains a global veterinary and public health concern. However, information regarding these filarids and their epidemiological patterns remains scarce in Malaysia. The present study aimed to determine the infection rate and associated risk factors of filarial parasites in dogs in Malaysia.
METHODS: A total of 399 dog blood samples were collected from veterinary hospitals and animal shelters in Malaysia to determine the infection rate and associated risk factors via a combination of microscopic, serologic and molecular diagnostic techniques.
RESULTS: Two species of canine filariae identified in this study were Dirofilaria immitis (6.5%) and Brugia pahangi (1.3%), and their infections were associated with cross breed, medium size and short hair (p
Pathogens in ectoparasites from free-ranging animals: Infection with Rickettsia asembonensis in ticks, and a potentially new species of Dipylidium in fleas and lice

Low VL, Prakash BK, Tan TK, Sofian-Azirun M, Anwar FHK, Vinnie-Siow WY, et al.

Vet Parasitol, 2017 Oct 15;245:102-105.
PMID: 28969827 DOI: 10.1016/j.vetpar.2017.08.015

Vector-borne infections are persistent public health threats worldwide. In recent years, a number of mosquito-borne viruses have emerged or re-emerged to cause major disease outbreaks. Other vector-borne pathogens, however, remain understudied and much neglected especially in the developing regions of the world including Southeast Asia. In this study, the brown dog tick Rhipicephalus sanguineus sensu lato, cat louse Felicola subrostratus, and cat fleas Ctenocephalides felis and Ctenocephalides orientis collected from free-ranging cats and dogs in Malaysia were molecularly screened for the presence of Bartonella and Rickettsia bacteria, and Dipylidium tapeworm. Our results showed the presence of Bartonella clarridgeiea, Bartonella henselae (lineage Marseille and lineage Houston-1), and Rickettsia sp. in C. felis. We also detected Rickettsia asembonensis in C. orientis and R. sanguineus s.l. Additionally, this study provides the first documentation on a potentially new species of Dipylidium infecting F. subrostratus and C. felis. Our results highlight the role of ectoparasites from free-ranging animals including cats and dogs, in harboring multiple transmissible pathogens.
Fulltext Identification of potential vectors of Dirofilaria immitis and Brugia pahangi (Spirurida: Filariidae): First observation of infective third-stage larva of B. pahangi in Culex quinquefasciatus (Diptera: Culicidae)

Vinnie-Siow WY, Low VL, Tan TK, Wong ML, Leong CS, Ahmad NW, et al.

Pathog Glob Health, 2022 Sep;116(6):356-364.
PMID: 35287548 DOI: 10.1080/20477724.2022.2035624

Information on the mosquito species that transmit canine filariosis is scanty. Hence, an experimental study was conducted to identify the potential vectors responsible for the transmission of D. immitis Leidy and B. pahangi Buckley & Edeson. A total of 367 mosquitoes belonging to six species containing both laboratory and field strains (i.e. Aedes togoi Theobald, Aedes aegypti Linnaeus, Aedes albopictus Skuse, Culex quinquefasciatus Say, Culex vishnui Theobald and Anopheles dirus Peyton & Harrison) were used in this study. All mosquitoes were artificially fed on either D. immitis or B. pahangi microfilariae (mfs) infected blood by using the Hemotek™ membrane feeding system. Out of 367 mosquitoes, 228 (64.9%) were fully engorged. After feeding on D. immitis (20%) and B. pahangi (33%) mfs positive blood, the mortality rates for Cx. quinquefasciatus were found to be slightly lower than that of other species of mosquitoes. On the other hand, majority of An. dirus were found to be incapable to withstand the infection of mfs as the mortality rates were relatively high (D. immitis = 71.4%; B. pahangi = 100.0%). Brugia pahangi was detected in Ae. togoi and Cx. quinquefasciatus with infection rates of 50% and 25%, respectively. Aedes togoi was the only species infected with D. immitis with an infection rate of 69%. Our results showed that Ae. togoi was an excellent experimental vector for both D. immitis and B. pahangi. This study also documented the observation of B. pahangi, for the first time in the head region of Cx. quinquefasciatus under a laboratory setting.
Detection of Hepatozoon canis in the Brown Dog Tick and Domestic Dogs in Peninsular Malaysia

Prakash BK, Low VL, Tan TK, Vinnie-Siow WY, Lim YA, Morvarid AR, et al.

J Med Entomol, 2018 Aug 29;55(5):1346-1348.
PMID: 29788335 DOI: 10.1093/jme/tjy081

Hepatozoon canis has been widely reported in dogs. Its prevalence in ticks, however, has not been well-established. Here we determine the occurrence of Hepatozoon DNA in the brown dog tick Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) sensu lato (s.l.) and domestic dogs from Peninsular Malaysia using a polymerase chain reaction (PCR) assay based on amplification of the 18S ribosomal RNA coding sequence. Our results revealed a relatively low prevalence of H. canis DNA in both R. sanguineus s.l. (0.7%) and dogs (3.33%). This study represents the first report of H. canis DNA in R. sanguineus s.l. in Malaysia, highlighting the risk of this infection in dogs.
Fulltext Contrasting evolutionary patterns between two haplogroups of Haematobia exigua (Diptera: Muscidae) from the mainland and islands of Southeast Asia

Low VL, Tan TK, Prakash BK, Vinnie-Siow WY, Tay ST, Masmeatathip R, et al.

Sci Rep, 2017 07 19;7(1):5871.
PMID: 28724923 DOI: 10.1038/s41598-017-05921-w

Uncovering the hidden diversity and evolutionary history of arthropods of medico-veterinary importance could have significant implications for vector-borne disease control and epidemiological intervention. The buffalo fly Haematobia exigua is an obligate bloodsucking ectoparasite of livestock. As an initial step towards understanding its population structures and biogeographic patterns, we characterized partial cytochrome c oxidase subunit I (COI) and cytochrome b (Cytb) sequences of H. exigua from three distinct geographic regions in Southeast Asia. We detected two distinct mitochondrial haplogroups of H. exigua in our surveyed geographic regions. Haplogroup I is widespread in the Southeast Asian mainland whereas haplogroup II is generally restricted to the type population Java Island. Both haplogroups were detected co-occurring on Borneo Island. Additionally, both haplogroups have undergone contrasting evolutionary histories, with haplogroup I exhibited a high level of mitochondrial diversity indicating a population expansion during the Pleistocene era dating back to 98,000 years ago. However, haplogroup II presented a low level of mitochondrial diversity which argues against the hypothesis of recent demographic expansion.