Dermacentor auratus Supino, 1897 (Acarina, Ixodidae) reported from Wayanad, Kerala

Sir,

The species of ixodid ticks reported from Kerala include, Rhipicephalus (Boophilus) annulatus, R. (B.) microplus, R. (B.) decoloratus, R. sanguineus, R. haemaphysaloides, R. turanicus, Haemaphysalis bispinosa, H. intermedia, H. aculeata, H. cuspidata, H. knobigera, H. turturis, H. spinigera, Hyalomma anatolicum, H. marginatum isaaci, H. hussaini, Amblyomma integrum, Nosomma monstrosum, N. keralensis1,2. The available literature does not show the report of any species of Dermacentor from Kerala. Various species of Dermacentor are recognized as vectors and reservoirs of bacilli, piroplasms, theilerias, viruses and reckettsiae3. This communication focuses on the identification of an adult male Dermacentor auratus from a man native of Wayanad district of Kerala, India.

A male labourer working at College of Veterinary and Animal Sciences, Pookot, Wayanad, Kerala, reported on February 20, 2009 about an attachment of tick on his leg while he was returning from his home through the college campus, which shares its boundary with the reserve forest. Bite had occurred only a few minutes back so the tick could be removed gently without damaging the mouth parts. The specimen was observed under a stereozoom microscope (Labomed, India) for species identification3–5 and photographed.

The removed single tick was identified as male D. auratus Supino, 1897 (Acarina, Ixodidae). Size of the tick was 7mm (length from capitulum to middle festoon) × 5mm (maximum breadth at its mid length). Scutum, capitulum and legs were highly ornate. Hypostome was short, spatulate, with a dentition of 3/3. A pair of eyes was present at the level of second coxae. More or less raised brown base colour markings characteristic of D. auratus were present on the dorsal scutum (Fig. 1a). Large punctuation interspersed by minute ones was noticed on the dorsal aspect of scutum while these were not observed on the brown raised areas. Festoons contained 11 bulges. On the ventral side, coxae increased in size from I to IV Fig. 1b), which is also a typical characteristic of Dermacentor spp. Palps were longer than basis capitulum, spiracular plates were ovate with a short narrow tail; external and internal spurs of coxa I were well separated.

Fig. 1.

(a): Dorsal view of male D. auratus(40X). (b) Ventral view of male D. auratus(40X).

There are 30 species of Dermacentor reported from all over the world, of which only three viz., D. atrosignatus, D. auratus, D. raskemensis occur in India. D. auratus has been recorded from hosts like man, cattle, deer, buffalo, wild boar and small mammals in different States of the country like Arunachal Pradesh, Assam, Bihar, Himachal Pradesh, Jammu & Kashmir, Orissa, Karnataka, Madhya Pradesh, Maharashtra, Punjab, Uttar Pradesh, and West Bengal6–8 (Fig. 2). The present report is perhaps the first record of bite of a human being by an adult male D. auratus from Kerala.

Fig. 2.

Distribution of D. auratus and Kyasanur forest disease (KFD) in India [Source: Refs 6–8 and present report].

D. auratus has already been reported to carry many recketsiae and viruses. Anaplasma sp. strain AnDa465, a genotype of Anaplasma platys and Rickettsia sp. strain RDla420 were detected from these ticks collected from dogs and bear respectively9. D. auratus was also identified to carry Kyasanur forest disease (KFD) virus10 which causes a fatal zoonotic viral disease reported from KFD region of Karnataka.

Wild pigs, deer, and possibly the python are reported to be the host for adults11. Bite of a nymphal stage of D. auratus on the upper eyelid of a man has been previously reported from Kolkata12. Man is frequently infected by nymphs of these ticks. But in the present case, the bite was due to an adult tick on man. Spread of this tick might have occurred from D. auratus prevalent Kyasanur forest and surrounding area of Karnataka State to the neighboring district Wayanad of Kerala due to migration of wildlife or transportation of livestock.