Hippobosca longipennis--a potential intermediate host of a species of Acanthocheilonema in dogs in northern India

Abstract

Background: Hippobosca longipennis (the 'dog louse fly') is a blood sucking ectoparasite found on wild carnivores such as cheetahs and lions and domesticated and feral dogs in Africa, the Middle East and Asia, including China. Known as an intermediate host for Acanthocheilonema dracunculoides and a transport host for Cheyletiella yasguri, it has also been suggested that H. longipennis may be a vector for other pathogens, including Acanthocheilonema sp.? nov., which was recently reported to infect up to 48% of dogs in northern India where this species of fly is known to commonly infest dogs. To test this hypothesis, hippoboscid flies feeding on dogs in Ladakh in northern India were collected and subjected to microscopic dissection.

Results: A total of 12 infective larvae were found in 10 out of 65 flies dissected; 9 from the head, 2 from the thorax and 1 from the abdomen. The larvae averaged 2, 900 (± 60) μm in length and 34 (± 5) μm in width and possessed morphological features characteristic of the family Onchocercidae. Genetic analysis and comparison of the 18S, ITS-2, 12S and cox-1 genes confirmed the identity of the larvae as the Acanthocheilonema sp.? nov. reported in dogs in Ladakh.

Conclusion: This study provides evidence for a potential intermediate host-parasite relationship between H. longipennis and the canine Acanthocheilonema sp.? nov. in northern India.

Figure 1

Adult specimen of the dog fly, Hippobosca longipennis found infesting dogs in Ladakh, India.

Figure 2

An infective larva of Acanthocheilonema sp.? nov. in situ within the head of a Hippobosca longipennis fly.

Figure 3

The heart-shaped of the dorsal solenidion on genu I of the first leg confirms the mite species as Cheyletiella yasguri.

Figure 4

The subterminal lateral caudal appendage of the infective larvae of Acanthocheilonema sp.? nov., a characteristic feature of the infective larvae from family Onchocercidae.

Figure 5

Un-rooted phenogram construction of the ITS-2 gene showed 100% bootstrap placement for all nine Acanthocheilonema larvae isolated from H. longipennis sequences together with microfilaria sequence from previous study, using the Neighbour-Joining algorithm. Bootstrap values at nodes indicate percentage calculated in 1000 replicates.

Figure 6

Un-rooted phenogram construction of the 12S gene using the Neighbour-Joining algorithm. Bootstrap values at nodes indicate percentage calculated in 1000 replicates. The phenogram showed 100% bootstrap placement for all nine Acanthocheilonema larvae isolated from H. longipennis sequences together with microfilaria sequence from previous study and forming a sister group with other species of Acanthocheilonema,

Figure 7

Un-rooted phenogram construction of the cox-1 gene showed 100% bootstrap placement for all nine Acanthocheilonema larvae isolated from H. longipennis sequences together with microfilaria sequence from previous study and forming a sister group with other species of Acanthocheilonema, using the Neighbour-Joining algorithm. Bootstrap values at nodes indicate percentage calculated in 1000 replicates.