Fish as the natural second intermediate host of gnathostoma spinigerum

Abstract

Gnathostomosis is a helminthic disease most frequently occurring in Thailand. Human infections are found to be caused solely by Gnathostoma spinigerum, although five species of the worm exist in the country, and three of them are capable of infecting man. In Thailand, 47 species of vertebrates-fish (19), frogs (2), reptiles (11), avians (11) and mammals (4) – were reported to serve naturally as the second intermediate (and/or paratenic) hosts of G. spinigerum. Among these animals, fish, especially swamp eels (Monopterus albus) were found to be the best second intermediate/paratenic hosts of the worm on the basis of having the highest prevalence rate and the heaviest infection intensity. However, the scientific names of these fish have been revised and changed from time to time. Therefore, for clarification and consistency, we summarize herein the currently used scientific names of these 19 species of fish together with their illustrations. We also report one additional species of fish, Systomus orphoides (Puntius orphoides), which has been first recorded as a naturally infected second intermediate host for G. spinigerum. The current scientific names of the 20 fish species, with their previous names and Thai names in parentheses, are as foloow: 1. Anbas testudineus (same.pla mo thai), 2 Arius caelatus (Tachysurus caelatus : pla kot), 3. Boesemania microlepis (Nibea soldado : pla ma), 4. Channa striata (Ophicephalus striatus :pla chon), 5. Channa micropeltes (Ophicephalus micropeltis : pla Chado), 6. Channa Lucius (Ophicephalus Lucius : pla krasong), 7. Clarias batrachus (same, pla duk dan), 8. Clarias microcephalus (sam, pla duk ui), 9. Chitala ornate (Notopterus chitala : pla krai), 10. Kryptopterus cryptopterus (same, pla kha kai), 11. Macrognathus siamensis (same, pla lot chut), 12. Mastacembelus armatus (same, pla krathing dam), 13. Micronema apogon (Kryptopterus apongon : pla nam ngoen), 14. Monopterus albus (Fluta alba : pla lai na), 15. Ompok krattensis (Ompok bimaculatus : pla nua on, pla cha-on), 16. Ophisternon bengalense (Synbranchus bengalensis : pla lat, pla lai), 17. Systomus orphoides (Puntius orphoides : pla kaem cham), 18. Trichogaster pectoralis (same, pla salit), 19. Trichogaster microlepis (same, pla kradi nang), 20.Trichogaster trichopterus (Trichopodus trichopterus : pla kradi mo).