The life cycle of Haplorchis pumilio (Trematoda: Heterophyidae) from the Indian region

Abstract

The life cycle of the heterophyid fluke, Haplorchis pumilio is elucidated for the first time from the Indian region. Various stages in the life cycle were established based on observations made on natural infections found in snails and fish in a freshwater stream at Visakhapatnam, India and experimental infections carried out in the laboratory. The thiarid snail, Thiara tuberculata served as the first intermediate host and a wide range of freshwater fish as second intermediate hosts. Natural infections with adult flukes were found in the piscivorous birds Ardeola grayii and Bubulcus ibis. Adults were raised experimentally in day-old chicks. Distinguishing features of the cercaria of H. pumilio are: a large body size (200-224 x 92-96 micro m), body-tail ratio of 1:2.1 and densely distributed pigment granules in the parenchyma imparting a brownish tinge to the body. Natural infections with metacercariae were found in the freshwater fish Channa punctatus, C. orientalis, Puntius sophore, Gambusia affinis and fingerlings of Cyprinus carpio and Liza macrolepis. Additionally, experimental infections were established in Therapon jarbua, Esomus danricus and Oreochromis mossambica. Metacercariae were embedded in the caudal muscles of fish and heavy infections induced mortality. Metacercariae were infective at about 15 days of age.

Morphological Characteristics and Phylogenetic Trends of Trematode Cercariae in Freshwater Snails from Nakhon Nayok Province, Thailand

“…A relationship was shown among the 6 clades according to the specific type of cercariae; for example, the clade Echinostomatida/Echinostomatidae group was found to be able to develop into the adult stage, which was in accordance with the findings of several previous reports [4,11,32]. The specimens of parapleurolophocercous cercariae in the clade can develop into intestinal trematodes in the family Heterophyidae, particularly H. taichui [8,33–36], megalurous cercariae can develop into avian eye trematode in the family Philopthalmidae [3], and furcocercous cercariae can develop into the family Cyathocotylidae [3]. Finally, xiphidiocercariae that were examined in this study developed into the family Lecithodendriidae, Prosthogonimidae, and Plagiorchiidae, namely, Prosthogonimus cuneatus, Ganeo trigrinus, Paralecithodendrium chilostomum , and Lecithodendrium sp.…”

Higher attack rate of fish-borne trematodes (Heterophyidae) in common carp fingerlings (Cyprinus carpio) at lower fish weight

“…Haplorchis and Centrocestus metacercariae that were already present in fish before exposure had, in this period, the opportunity to become mature and identifiable (Komiya 1966;Umadevi and Madhavi 2006). Time from exposure to digestion of 7 days was considered short enough to distinguish undeveloped metacercariae from developed metacercariae that were present in fish before experimental exposure (Boerlage et al 2011) and long enough for undeveloped metacercariae to develop a cyst (Komiya 1966) to protect the metacercariae during digestion.…”

Human intestinal flukes Haplorchris taichui and Haplorchris pumilio in their intermediate hosts, freshwater snails of the families Thiaridae and Pachychilidae, in southern Thailand

“…Hence, this worm may cause non-acute or chronic inflammation and segmental enteritis in patients (Sukontason et al 2001). In addition, H. pumilio and H. taichui cercariae cause considerable fish mortality (Umadevi & Madhavi 2006). Furthermore, the possibilities of implementing control measures should aim at reducing trematode infections in farmed freshwater fishes that would help to improve the life quality of people in local communities.…”