Freshwater fishes of thailand as experimental intermediate hosts for Capillaria philippinensis

lnternntional Journalfar Parasitolog.v, Vol. 9, pp. 105-108. Pergmon Press Ltd. 1979. Printed in Greuf Brifain.

FRESHWATER FISHES OF THAILAND AS EXPERIMENTAL INTERMEDIATE HOSTS FOR CA PILL.4 HA P~~~~PP~N~N~~S M. BHAIBULAYA, S. INDRA-NGARM and M. ANANTHAPRUTI Department

of Helminthology, Faculty of Tropical Medicine, Mahidol University, 420/6, Rajvithi Road, Phyathai, Bangkok 4, Thailand (Received 28 February 1979)

Abstract-BHAIBULAYA

M., INDRA-NGARM S. and ANANTHAPRUTI M. 1979. Freshwater fishes of Thailand as experimental intermediate hosts for Capillaria philigpinensis. The International Journal for Purasifo~ogy 9: 10% 108. Nine species of freshwater fishes from Thailand have been exposed to infection with embryonated eggs of Capillariaphilippinensis. The eggs were fed to fishes with food or through a polyethylene tube. After lo-30 days larvae capable of establishing intestinal capillariasis in Mongolian gerbils were recovered from six fish species: Cyprinus carpio, Pun&s goniono~u.~,Aplocheilu~ panchax, Gambusia ho&rookii, Rasbora borapefensis, and Trichopsis vitfafus. Larvae were not recovered from Tilapia nilotica, Osteochilus hasseltii and Trichogaster frichopterus. Five human cases of intestinal capillariasis have been reported from widely scattered areas of Thailand and the natural intermediate and definitive hosts remain to be determined.

INDEX

KEY WORDS:

Capilravia phi/~pine~js;

INTRODUCTION IN THE

first reports

Philippines,

of intestinal

freshwater

capillariasis in the fish was one of the suspected

sources of infection (Cabrera, Canlas & Dauz, 1967; Dizon, Watten and Associates, 1969) and in describing the parasite Capiliaria philippinensis, Chitwood, Velasquez & Salazar (1968) compared the parasite to similarly small capillatiids from fishes. In further studies Cabrera, Baltazar, Caviles, Domingo, Gonzaga, Lingao & Campos (1969) reported the recovery of C. philippinensis eggs from the sediment of homogenized heads of Eleotris rn~~~nosorn~ and Arnb~s~~s commerso?~i, collected from rivers in the endemic area of the Philippines and suggested that human infection was acquired by eating raw or insu~cientiy cooked fishes harbouring embryonated eggs of the nematode. Cross, Banzon, Clarke, Basaca-Savillal Watten & Dizon (1972), however, showed that C. phiiippinensi~ eggs hatched in experimentally infected fish (E. melunoscima, A. c~rnrners~~~and Apugon sp. = Hyp.selotris biparfitu) and that the larvae from these fish developed into adults in the small intestine of monkeys. These authors also reported finding Apogon sp. (== H. bipartitu) naturally infected with capillariid larvae. In later studies Cross, Banzon & Singson (I 978) demonstrated natural transmission of the parasite by feeding H. bipurtita from Philippine lagoons to Mongolian gerbils.

Thailand;

freshwater

fish, intermediate

host.

In Thailand intestinal capillariasis has been reported from several areas of the country (Fig. 1) (Pradsundarasar, Pecharanond, Chintanawon~ & Ungthavorn, 1973; Sanpakit, Suksungvol & Bhaibulaya, 1974; Ratanachaiyavongs, Chintanawongs, Piyachon, Wongtongsri & Israsena, in press; Muangmanee, Aswapokee & Vanasin, 1977) and in the report by Bhaibu~aya, Benjapong & Neoypatimanond (1977) it was suggested that freshwater fishes, habitually eaten raw in some areas of the country, probably serve as natural intermediate host for C. philippinensis, and consequently the source of human infection. Experiments have therefore been carried out to determine whether certain species of freshwater fishes in Thailand could serve as experimental intermediate host for the parasite. This paper presents the results of these experimental studies. MATERIALS

AND METHODS

Nine species of freshwater fish commonly found in Thailand were used: Cyprhzus carpio (Pla Nai), Tilapiu nilofica (Pla Nil), and Puntius gonionotus (Pla Tapien Khao) were obtained from a commercial hatchery. Apiocheilus panchax (Pia Huatakua), Gambusia t?olbrookii (Pla Harngnokyoong), Osteochilus hosseltii (Pla Sroinokkhao), Rasbora bnrapeiensis (Pla Sew), Trichagaster irichopterus (Pla Kradee), and Trichopsis vitiatus (Pla Krim) were obtained from the canals and ponds around Bangkok (local names are in the brackets). 105

M.

BHAIBULAYA.

S. INDRA-NGARMand M. ANANTHAPRUT~

I.J.P. VOL.

9. 1979

RESUL,TS

Phanom

1. Chao Phya River 2. Bang Pakong River 3. Pasak River

C. p~~li~pjnei?~~~Iarvae were found to develop in six of the nine species of the fish tested (Table 1). The numbers and species of fishes used and those found positive and the maximum numbers of the larvae recovered are shown in Table 1. By forced feeding C. F~il~p~~~ze~~~~~ was found to deveiop in only three species. The number and species of fishes used and those found positive and the maximum numbers of the larvae recovered are shown in Table 2. The larvae recovered from the positive fishes were morphologically similar, cylindrical in shape, bluntly rounded at both ends and measured 300326 pm in length (Fig. 2). Twenty-five to 28 days later, larvae from each of the six fish species were fed separately to the six gerbils. C. phifippirremis eggs were recovered from the faeces of all six gerbils. The gerbils were killed 4-5 weeks after infection and larvae and adults of C. philippinemis were recovered in each case.

4. Mut River 5. Songkhfam

River

% FIG. 1. The provinces and the main rivers of Thailand

from which the intestinal capillariasis reported.

cases have been

The size of the fishes were recorded (Tables 1 & 2) and at least 20 fish of each species were examined for possible natural infection of C. philippinensis; all were negative. Eggs of C. philipp~~e~~swere obtained from the faecal specimens from the fifth person in Thailand found with intestinal cap~~~~ias~s (~ha~b~laya et al., 1977). The eggs were washed several times with dechlorinated tap water until the supernatant was clear. The sediment containing eggs was transferred into the small Petri dishes and embryonated at 28-32°C for 2-3 weeks. The eggs required at least IO-14 days to embryonate and to become in-

fective for fish intestine (Cross, Banzon, Clarke, BasacaSevilla, Watten & Dizon, 1972). The cultures were concentrated and the embryonated eggs were given twice or three times to the fishes either in their food (self feeding) or by forced feeding. BY self feeding, the embrvonated eggs were mixed with commercial fish-food and fed to fish which had been deprived of food for 24 h. Forced feeding of eggs was accomplished by inserting a polyethylene tube into the mouth of fishes. Approximately 40-50 eggs were fed each time through the tube. After 10-30 days the fishes were dissected and examined for larvae in the intestine. The larvae recovered were pooled according to species of fish and fed to six Monoglian gerbils (~~rjones ~~gujc~~at~~. Two weeks after exposure to infection, faecai specimens from the gerbils were examined for C. p~i~ip~j~e~si~eggs. The gerbils were killed 4-5 weeks postinfection to reconfirm C. philippinmris infections.

C. carpiu a cyprinoid fish from China was introduced into Thailand. it has successfully adapted to the ponds, canals and rivers in many parts of the country. P. go~io~otus occurs throughout the length of Thailand but is commonest in the rivers of theeentral Thailand, especially the Chao Phya, the Nakhon Nayok (short tributary of the Bang Pakong River), the Pasak (tributary to the Chao Phya which enters from the Northeast near Ayudthya), the Sikuk (tributary of the Chao Phya) and the Mekong. This species is caught in large quantities for domestic consumption. R. borapetensis is a small fish, abundant, and found chiefly in Bung Borapet (an artificial fake) in Nakhon Swan Province, Northern Thailand. It can also be found in the rivers and ponds in other regions. T. vittatus is distributed throughout the Central, Peninsular, and Southern Thailand and common in the small weedy streams and sometimes in the canals. A. ~u~~~~~ is a coastal species and never found far from the sea. It usually abounds in drains, ditches and pools connected io rivers. At times it can also be found in mountain streams. C. hdbrookii was introduced to Thailand in 1929 from Palestine and has a widespread distribution throughout the country (Smith, 1965). Five human cases of intestinal capillariasis have been reported from various parts of Thailand. Four of them were from the Provinces situated on the main rivers of Thailand and where the people habitually eat raw freshwater fishes. These provinces are Saraburi, Sutin, Phechabun and Nakhon Phanom. In these areas the small freshwater fishes (less than 10 cm in length) are generally eaten raw. The fishes are prepdred for consumption by chopping the whole fish into small pieces and seasoning

Experimental intermediate hosts for Capiilaria phifippinensis

I.J.P. VOL. 9. 1979

FIG. 2. The Iarva of Capjilar~apbii~pine~~s recovered from smah intestine of G. ~orb~ook~i10 days post infection. TABLE I-EXPERIMENTAL INFECTIONOF FRESHWATERFISHESBY --

C. curpio

P. gonionotus A. panchax G. holbrookii R. borapetensis T. vittatm T. nilotica T. tricbopte~ils 0. hasseltii

.-

Size in length (cm)

No. fish used

2.1-6.8 2.540 3.442 1.2-3.5 2.0-4.8 2.5-5.4 6.8-9.8 7.0-8.4 6.0-10.5

244 20 17 231 9 31 30 IO 2

TABLE 2-EXPERIMENTAL -_

---

FEEDIKG

Maximum number of

Fish species

--

SELF

--.____

INFECTION

OF FRESHWATER

No. fish positive

52 15 7 62

larvae recovered

10 8 8 22 5 16 -

(21.3%) (75%) (41.2%) (26.8%)

10 (372.2%) 0 0 0

FISHES

BY FORCED

FEEDIKG

.-.

Fish species

C. carpio A. panchax T. vittatus T. nilotica T. trichopterus 0. haneltii

Maximum number of

Size in length (cm) I._ 2.1-68 3.4-4.2 2.5-5.4 6.8-9-S 7.0-8.4 6+-10.5

No. fish used

No. fish positive

6 ::

5 5 4 0 0 0

with the juice from fermenting salted fish, lime juice and red peppers. Some people, however, occasionally chew the fish freshly caught. Among the fishes found to serve as experimental intermediate hosts, C. curpio, P. gonionotus, R. barapetensis and T. vittatus are commonly eaten raw, while A. panchax and G. holbrookii are not used as food.

5 5 5

larvae recovered .~ 6 5 IO -

It has been recently demonstrated that fish in the Philippines can transmit C. philippinensis naturally. On three separate occasions H. bipartita from a lagoon in the endemic area lead to C. p~izip~~izensis infection after being fed to gerbils (Cross, Banzon & Singson, 1978). The present study shows that C. phifippinensis possesses a low intermediate host-

108

M.

BHAIBULAYA, S. INDRA-NGARM and M. ANANTHAPRUTI

specificity. Six out of nine species of the freshwater fishes tested were able to serve as intermediate hosts. The five cases of intestinal capillariasis reported thus far in Thailand are from widely scattered areas, unlike the Philippines where cases have been reported only from the coastal areas of North and East Luzon. It may be due to eating habits of humans since only the people in Northern Luzon eat uncooked foods, and populations throughout most of Northeastern and some of Central parts of Thailand eat raw food. No definitive host other than humans have been found although a very large number of animals have been examined in the Philippines (Cross, Banzon & Singson, in press). The natural definitive host, if one exists could be limited in distribution in the Philippines, and be widely distributed in Thailand. In addition the present results provide important information that could be applied to future epidemiological studies of C. philippinensis in Thailand. The authors, however, suspect that a fish eating mammal or bird may be the true definitive host and man on accidental host.

I.J.P. VOL. 9. 1979

CABRERA B. D., CANLAS B. & DAUZ U. 1967. Human intestinal capillariasis-III. Parasitological features and management. Arta Medica Philippina 4: 92-103. CABRERA B. D., BALTAZAR R., CAVILES A. P., DOMINGO E., GONZACA A., LINGAO A. & CAMPOS P. C. 1969.

Capillaria

from

philippinensis

Pudoc,

llocos

eggs demonstrated in fish Sur. Journal of the Philippine

Medical Association 45 : 275. CHITWOOD M. B., VELASQUEZC. & SALAZAR N. G. 1968.

CapiUaria philippinensis

sp. n. (Nematoda:

Trichinelof man in the Philippines.

lida) from the intestine

Journal of Parasitology 54: 368-371. CROSS J. H., BANZON T., CLARKE M. D., SAVILLA V., WATTEN R. H. & DIZON J.

BASA~A-

J. 1972. Studies on the experimental transmission of Capillaria philippinensis in monkey. Transactions of the Royal Society of Tropical Medicine and Hygiene 66: 819-827. CROSS J. H., BANZON T. & S~NGSONC. (1978). Further studies on Capillaria philippinensis: Development of the parasite in the Mongolian gerbil. Journal of Parasitology 64: 208-213. DIZON J. & WATTEN R. H. 1969. Preliminary observations on a new disease in man: intestinal capillariasis.

Journal of the Philippine Medical Association 45: 5-20. MUANGMANEE L., ASWAPOKEE N. & VANASIN B., 1977. Intestinal Capillariasis: Report of the fourth case in

Thailand. Siriraj Hospital Gazette 29: 439-449. Acknowledgements-The

authors would like to express their sincere thanks to Professor S. Vajrasthira, Head, Department of Helminthology, Mahidol University for giving them the facilities to perform the present experiments. They are very grateful to Dr. J. H. Cross, the Scientific Director and Head of Department of Medical Ecology, U.S. Naval Medical Research Unit No. 2, Taipei, Taiwan, for providing the Mongolian gerbils, and for reading and criticizing the manuscript.

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longkarn Medical Journal. SANPAKIT S., SUKSUNGVOL S. & BHAIBULAYA M. 1974. Intestinal capillariasis from Saraburi Province, Thailand. Report of the second case. Journal of the Medical

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