ANGIOSTRONGYLUS CANTONENSIS : AN EMERGING ZOONOSIS CAUSING EOSINOPHILIC MENINGITIS IN JAMAICA

by Cecelia Hall 1, J.F. Lindo 1, C. Cunningham-Myrie 2,
K. Bishop 1, M.L. Eberhard 3, & R.D. Robinson 1

This poster presentation was made by Cecelia Hall, graduate student in the Department of Life Sciences, at the International Conference on Emerging Infectious Diseases, held in Atlanta, Georgia, and sponsored by the US Centers for Disease Control and Prevention.

The paper attracted considerable interest from delegates at the conference, not least because it was the only one that depicted a helminth (worm) infection as an emerging disease concern.

Funding for the production of the poster and for Cecelia’s trip was provided by the Board for Graduate Studies and Research and the Department of Life Sciences.

The following is the abstract of the paper, which was published in the Proceedings of the conference.

Angiostrongylus cantonensis is a naturally occurring nematode parasite of the pulmonary arteries of rats, mainly in the Pacific Basin. The parasite is also the most common infectious cause of eosinophilic meningitis (EM) in humans in the tropics and subtropics. Human infections with A. cantonensis are largely a consequence of the zootic status of the parasite and human food preferences, and involve the ingestion of third stage larvae.

In Jamaica, the first case of A. cantonensis infection was documented in 1994. Since then, several persons, travellers and residents alike, have presented with a combination of EM and positive serology for A. cantonensis. Some fatalities have ensued.

In this report, we present current information on the distribution and levels of infection of A. cantonensis in rats and snails in Jamaica.

Three hundred and thirty-five rats (218 Rattus rattus and 117 R. norvegicus) were collected from all parishes in Jamaica. The cardiopulmonary system of each was dissected and examined for adult worms.

Terrestrial snails were also collected: 96 Thelidomus asper, 47 Orthalicus jamaicensis, 20 Anoma sp., 16 Pluerodonte sp., and 28 Tudora sp. The foot of each snail was digested with 0.01% pepsin and 0.7% HCl solution, and examined for larvae.

One hundred and ten (~33%) of the 335 rats collected were infected with A. cantonensis. The prevalence in R. rattus was 39.4% (n = 218), compared with 20.5% (n = 117) in R. norvegicus (chi 2 = 11.53; p < 0.001). Prevalences of infection in the four Regional Health Authority areas of Jamaica are presented in Table 1. The mean intensity of infection was 13 ± 2 (range = 2 – 76) worms.

 Table 1. Prevalence of A. cantonensis in Rats and Snails in Jamaica

Among the snails, A. cantonensis larvae were found only in Thelidomus asper. The overall prevalence was 15% (n = 196), and infected snails were found in the three parishes where collections were made.

Conclusions  

Angiostrongylus cantonensis is enzootic in wild rats and at least one species of land snail in Jamaica. R. rattus is the main reservoir of infection with A. cantonensis in the island: parasite prevalence and intensity estimates were significantly higher compared with R. norvegicus. Human eosinophilic meningitis has been serologically and histopathologically linked with A. cantonensis infections. Autochthonous transmission of A. cantonensis to humans is occurring in Jamaica.

1 The University of the West Indies, Mona

2 Ministry of Health, Kingston

3 Centers for Disease Control and Prevention, Atlanta, Georgia