Zoonotic Vectorborne Pathogens and Ectoparasites of Dogs and Cats in Eastern and Southeast Asia

Abstract

To provide data that can be used to inform treatment and prevention strategies for zoonotic pathogens in animal and human populations, we assessed the occurrence of zoonotic pathogens and their vectors on 2,381 client-owned dogs and cats living in metropolitan areas of 8 countries in eastern and Southeast Asia during 2017-2018. Overall exposure to ectoparasites was 42.4% in dogs and 31.3% in cats. Our data cover a wide geographic distribution of several pathogens, including Leishmania infantum and zoonotic species of filariae, and of animals infested with arthropods known to be vectors of zoonotic pathogens. Because dogs and cats share a common environment with humans, they are likely to be key reservoirs of pathogens that infect persons in the same environment. These results will help epidemiologists and policy makers provide tailored recommendations for future surveillance and prevention strategies.

Keywords: Southeast Asia; Zoonoses; cats; companion animals; dogs; eastern Asia; ectoparasites; parasites; pathogens; vector-borne diseases; vector-borne infections; vectors.

Figure 1

Geographic distribution and size of dog and cat samples in study of ectoparasites and vectorborne zoonotic pathogens of dogs and cats in Asia, 2017–2018. Highlighted areas represent the geographic regions from which samples were collected in China, Indonesia, Malaysia, the Philippines, Singapore, Taiwan, Thailand, and Vietnam.

Figure 2

Morphologic characteristics of ticks collected from dogs and cats in study of ectoparasites and vectorborne zoonotic pathogens of dogs and cats in Asia, 2017–2018. A–C) Male Rhipicephalus haemaphysaloides tick with hexagonal basis capitulum (A); typical sickle-shape adanal plates (B); and spiracular plate with comma shape, broad throughout its length (C). D–F) Male R. sanguineus tick with hexagonal basis capitulum (D); subtriangular adanal plates (E); and comma-shaped spiracular plate, elongated throughout its length (F). G) Female Haemaphysalis longicornis tick with enlarged lateral palp article II (double arrowhead), ventral spur on palp article III (arrow), and internal spur on coxa I (white arrowhead), relatively long and pointed. H) H. longicornis tick palp article III with retrograde dorsal spur (arrow) and cornua one third the length of the basis capitulum (arrowhead). I) Larva of Haemaphysalis wellingtoni palp article II slightly broader than article III, internal spur on coxa I (arrowhead) and strong and sharp ventral spur on palpal article III (arrow). J–K) Female Haemaphysalis campanulata tick with well-defined ventral spur (arrow) on palp article III, palp article II strongly salient laterally, with flared and bell-shaped posterior margin (arrowhead) (J) and with short cornua (arrow) (K). L) Ixodes sp. female tick with long palp (arrow) and short spur on coxa I (arrowhead). Scale bars in panels A, B, D, E, G, J, and L indicate 500 μm; scale bars in panels C, F, H, and K indicate 200 μm; scale bar in panel I indicates 100 μm.

Figure 3

Morphologic characteristics of fleas collected from dogs and cats in study of ectoparasites and vectorborne zoonotic pathogens of dogs and cats in Asia, 2017–2018. A) Ctenocephalides felis male flea head; B) C. felis female flea head showing acute anterior margin; C) C. canis male flea; D) Ctenocephalides orientis male flea; E) C. orientis female flea; F) Xenopsylla cheopis male flea with strongly rounded anterior margin and absence of ctenidia; G) C. felis flea with 6 setae-bearing notches (arrows) on the dorsal margin of the hind tibia; H) C. orientis flea with 7 setae-bearing notches; I) C. canis flea with 8 setae-bearing notches; J) C. felis flea with 2 setae on the lateral metonotal area (arrows); K) C. orientis flea with 2 setae; L) C. canis fleas with 3 setae. Scale bars indicate 200 μm.

Figure 4

Chewing lice collected from dogs and cats in study of ectoparasites and vectorborne zoonotic pathogens of dogs and cats in Asia, 2017–2018. A) Female Felicola subrostratus louse with triangular head and pointed anteriorly. The median longitudinal groove (arrowhead) on the head fits around the shaft of the hair of the host. Thorax is short and legs are small, ending with a single claw (arrow). B) Trichodectes canis male louse with short thorax, flattened head with quadrangular shape, broader than long; each leg with only 1 claw on tarsus (arrow). C) Heterodoxus spiniger female louse with subtriangular head, rounded anteriorly. The thorax is considerably longer than wide. Each leg has 2 claws on the tarsus (arrow). Scale bar indicates 1 mm.

Figure 5

Mites collected from dogs and cats in study of ectoparasites and vectorborne zoonotic pathogens of dogs and cats in Asia, 2017–2018. A) Otodectes cynotis female mite with greatly reduced last pair of legs (arrow); the third pair of legs terminates in 2 long and whip-like setae (double arrowhead). B) Sarcoptes scabiei male mite with strong and spine-like dorsal setae (arrow). C) Notoedres cati mite with narrow and not spine-like setae. D) Female Lynxacarus radovskyi cat fur mite with cylindrical and heavily striated idiosoma, well-developed head plate (double arrowhead) with convex posterior margin; propodosomal plate (arrowhead) with posterior margin broadly rounded, connected mediodorsally to head plate by a narrow-sclerotized band (arrow). E) L. radovskyi female mite genital apparatus (arrow) positioned between coxae III in female. F) L. radovskyi male mite with genital apparatus (arrow) positioned between coxae IV (arrow) and circular genital discs (arrowhead). Scale bars in panels A and D indicate 200 μm; scale bars in panels B, C, E, and F indicate 100 μm.

Figure 6

Thelazia callipaeda eyeworms collected from animals in China in study of ectoparasites and vectorborne zoonotic pathogens of dogs and cats in Asia, 2017–2018. A) T. callipaeda male eyeworm with buccal capsule (arrow); B) posterior end of male eyeworm with short and crescent-shaped spicule (arrow); C) anterior portion of T. callipaeda female eyeworm with vulva (arrow) located posterior to the esophagus-intestinal junction (arrowhead); and D) posterior end of female eyeworm showing anus (arrow) and phasmids (arrowhead). Scale bars indicate 200 μm.