A checklist and key to the tick fauna (Acari: Ixodidae, Argasidae) of Pulau Tioman, Malaysia

Host, season, habitat and climatic factors as drivers of Asian rodent tick (Ixodes granulatus) (Acari: Ixodidae) occurrence and abundance in Southeast Asia

The Asian rodent tick (Ixodes granulatus) occurs throughout much of Asia, it frequently bites humans, and zoonotic pathogens, such as Borrelia burgdorferi (sensu lato) and Rickettsia honei, have been detected within it. Unfortunately, the ecology of I. granulatus remains poorly known, including drivers of its abundance and the interaction ecology with its sylvatic hosts. To elucidate the ecology of this medically important species, the habitat preferences of I. granulatus were assessed in Singapore and Malaysia. Ixodes granulatus showed strong associations with old forest habitats, though across different age classes of old forest there was limited variation in abundance. Ixodes granulatus was absent from other habitats including young forest, scrubland, and parks/gardens. Within its sylvatic rodent hosts, a range of factors were found to be statistically significant predictors of I. granulatus load and/or infestation risk, including sex and body condition index. Male rodents were significantly more likely to be infested and to have higher loads than females, similarly, animals with a lower body condition index were significantly more likely to be infested. Proactive public health efforts targeted at preventing bites by this tick should carefully consider its ecology to minimise ecological overlap between humans and I. granulatus.

Ticks (Acari: Ixodidae) of three Timor-Leste reptiles: first country record of Amblyomma helvolum, with new interactions and an updated list of host species

We report on the presence of the ixodid tick Amblyomma helvolum on three species of reptiles from Timor-Leste. Among a total of 21 host specimens (lizards: 18 four-fingered skinks, Carlia sp. 'Meleotegi' and two forest skinks, Sphenomorphus sp. 'Meleotegi'; snake: one Coelognathus subradiatus) four were parasitized by ticks. Whereas nymphs were associated with the lizards, an adult male was retrieved from the snake. This report is the first of A. helvolum for Timor-Leste, the first for the skink genera Carlia and Sphenomorphus, and the first for C. subradiatus. We present a comprehensive table with updated taxonomy of known associations between A. helvolum and other vertebrates.

First Record of the Tortoise Tick, Amblyomma geoemydae (Cantor, 1847) (Acari: Ixodidae) Parasitizing a Tree Shrew, Tupaia glis (Scandentia: Tupaiidae) in West Malaysia

The tick genus Amblyomma Koch, 1844 (Acari: Ixodidae) has received little attention in Malaysia; therefore, its associated hosts and distribution records are poorly known. In this study, we collected six Amblyomma sp. individuals (two larvae and four adults) that infested a common treeshrew, Tupaia glis (Diard, 1820) (Scandentia: Tupaiidae) caught in a recreational area in Sungai Lembing, Pahang (West Malaysia). The adult female ticks were morphologically identified according to taxonomic keys prior to molecular identification using cytochrome oxidase subunit I (COI) and 16S rDNA genes. The ticks were genetically verified as Amblyomma geoemydae (Cantor, 1847) with 98%-99% similarity to the available GenBank sequences. Neighbor-joining (NJ) trees indicated that A. geoemydae was clearly distinguished from other Amblyomma ticks and this was supported with high bootstrap values. This paper is the first to report A. geoemydae ticks infesting T. glis and provides a new tick-host record from West Malaysia. This information is significant for further investigation, specifically on this tick species as potential vector of tick-borne disease (TBD) agents.

Soft ticks (Acari: Argasidae) in the island nations of Southeast Asia: A review on their distribution, associated hosts and potential pathogens

Soft ticks (Acari: Argasidae) are the second major family of the blood feeding metastriates and vectors of a number of viral and bacterial pathogens for both humans and animals. Despite the growing effort on tick surveillance and studies worldwide, there is still limited information on the soft tick distribution in the island nations of Southeast Asia, especially species that are medically and veterinarily important. With the aim to provide an overview of the current status of knowledge on soft tick distribution in the island nations of Southeast Asia (Malaysia, Singapore, Brunei, Indonesia, the Philippines and Timor-Leste), this article reviews the species of soft ticks (Acari: Argasidae) and their associated hosts and pathogens, with the addition of a pictorial summary and list of tick species discovered in this region. The most prevalent soft tick genus is Carios, and the host species most associated with findings of soft ticks in this region are bats, particularly of the Pteropodidae and Vespertilionidae families. Furthermore, the only known pathogen originating from soft ticks in the island nations of Southeast Asia was the Keterah virus, which was isolated from Argas pusillus tick in Malaysia.

Habitat impacts the abundance and network structure within tick (Acari: Ixodidae) communities on tropical small mammals

Ticks of small mammals pose a significant risk to public health but these hazards are poorly understood in the tropics due to the paucity of information on the disease ecology of ticks in these regions. Mapping and quantifying the diversity of small mammal/tick networks and the effects of habitat on these medically important systems is key to disease prevention. Singapore represents a microcosm of much of tropical Asia as it has a diverse, though poorly studied, community of ticks and small mammals. Singapore also has a range of terrestrial habitats exhibiting a gradient of degradation. Small mammals and their ticks were sampled across the island in four main habitat types (old secondary forest, young secondary forest, scrubland, urban) across 4.5 years. Four tick species were collected (Amblyomma helvolum, Dermacentor auratus, Haemaphysalis semermis, Ixodes granulatus) from 10 small mammal species. Habitat was found to have a significant effect on both the abundance and structure of tick communities on small mammals. Old secondary forest communities had the highest tick abundance, comparatively high connectance, niche overlap (among ticks), linkage density, and were the preferred habitat of the zoonotic tick I. granulatus. Therefore, future disease spillover is likely to emerge from small mammal-tick communities in old secondary forests.

Ticks and tick-borne pathogens in animals and humans in the island nations of Southeast Asia: A review

Ticks are blood-feeding ectoparasites and major vectors of pathogens that cause infectious diseases in humans and animals worldwide including mammals, birds and reptiles. Despite the growing scientific effort in the 20th century, there is still limited information on ticks and tick-borne pathogens in Southeast Asia, especially concerning medical, veterinary, socioeconomic and agricultural aspects in the island nations. This review provides an overview of the current state of knowledge of ticks and their pathogens in the island nations of Southeast Asia and peninsular Malaysia. We aim to stimulate further research studies on ticks and tick-borne pathogens of human and veterinary importance in this geographical region.