Genetic variation at 21 gene-enzyme systems was studied in a sample of an adult population of Anisakis typica (Diesing, 1860) recovered in the dolphin Sotalia fluviatilis from the Atlantic coast of Brazil. The characteristic alleles, detected in this population, made it possible to identify as A. typica, Anisakis larvae with a Type I morphology (sensu Berland, 1961) from various fishes: Thunnus thynnus and Auxis thazard from Brazil waters, Trachurus picturatus and Scomber japonicus from Madeiran waters, Scomberomorus commerson, Euthynnus affinis, Sarda orientalis and Coryphaena hippurus from the Somali coast of the Indian Ocean, and Merluccius merluccius from the Eastern Mediterranean. Characteristic allozymes are given for the identification, at any life-stage and in both sexes, of A. typica and the other Anisakis species so far studied genetically. The distribution of A. typica in warmer temperate and tropical waters is confirmed; the definitive hosts so far identified for this species belong to delphinids, phocoenids and pontoporids. The present findings represent the first established records of intermediate/paratenic hosts of A. typica and extend its range to Somali waters of the Indian Ocean and to the Eastern Mediterranean Sea. A remarkable genetic homogeneity was observed in larval and adult samples of A. typica despite their different geographical origin; interpopulation genetic distances were low, ranging from D(Nei)=0.004 (Eastern Mediterranean versus Somali) to D(Nei)=0.010 (Brazilian versus Somali). Accordingly, indirect estimates of gene flow gave a rather high average value of Nm = 6.00. Genetic divergence of A. typica was, on average, D(Nei)=1.12 from the members of the A. simplex complex (A. simplex s.s, A. pegreffii, A. simplex C) and D(Nei)=1.41 from A. ziphidarum, which all share Type I larvae; higher values were found from both A. physeteris (D(Nei)=2.77)
Seventy-four genera comprising approximately 140 named and 75 undetermined species of adult and larval nematodes are associated with about 330 named and 50 undetermined species of marine, brackish and freshwater fishes from Brazilian waters. These are listed with information on their hosts, habitat, distribution and records. A key to these parasites at the generic level is provided.
Pseudorhabdosynochus sulamericanus n. sp. from the gills of Epinephelus niveatus has a reniform proximal region of the cirrus-bulb which is divided in four chambers and contains a large, round reservoir of the male accessory glands, a partly sclerotised vagina which is enclosed in a muscular funnel cap and squamodiscs with 15-16 open concentric rows of elements. P. beverleyburtonae (Oliver, 1984) is redescribed from E. marginatus with additional morphological data. These are the first reports of Pseudorhabdosynochus spp. in South American Atlantic waters, where the potentiality for the mariculture of Epinephelus spp. is currently being evaluated. Pseudorhabdosynochus hargisi (Oliver & Paperna, 1984) n. comb. is proposed for Diplectanum hargisi.
Anisakid nematode larvae from Trichiurus lepturus off coast of Rio de Janeiro were studied using light, laser confocal and scanning electron microscopy, in addition to a molecular approach. Mitochondrial cytochrome c-oxidase subunit 2 (mtDNA cox-2), partial 28S (LSU) and internal transcribed spacers (ITS-1, 5.8S, ITS-2) of ribosomal DNA were amplified using the polymerase chain reaction and sequenced to evaluate the phylogenetic relationships between the nematode taxa. The morphological and genetic profiles confirmed that, of the 1,030 larvae collected from the 64 fish examined, 398 were analysed, of which 361 were Hysterothylacium sp. and 37 were Anisakis typica. Larvae of Hysterothylacium sp. were not identified to the species level due to the absence of similar sequences for adult parasites; however, the ITS sequence clustered in the phylogenetic tree with sequences of H. deardorffoverstreetorum, whereas an mtDNA cox-2 and LSU concatenated phylogenetic analysis demonstrated the presence of two clades, both of them under the same name as the larval H. deardorffoverstreetorum. Data on the occurrence of parasites during the winter and summer months were compared using the t-test. The greatest prevalence and intensity of infection were recorded for larval Hysterothylacium, with a prevalence of 51.56% and an intensity of up to 55 parasites per fish. The larval Anisakis exhibit a higher abundance and intensity of infection in the winter months, and those of Hysterothylacium during the summer. However, the t-test indicated no significant differences between the abundance and intensity of infection recorded during the months of collection for either of these larval nematodes. All sequences generated in this study were deposited in GenBank.
Although the Chiroptera represents a significant proportion (c.20%) of the mammalian fauna and South America has the highest diversity of bat species, only about a third of the known species in this region have had helminth parasites reported from them. This work represents the first comprehensive checklist of the helminth parasites (nematodes, acanthocephalans, trematodes and cestodes) of South American bats. The data were extracted from more than 120 references and are presented as a key to each group of parasites down to the generic level, with an indication of how the bats become infected, accompanied by a list of the species recorded for each genus. This is followed, in tabular form, by parasite-host and hostparasite checklists. The parasite-host list also includes their geographical distribution in South America (at the country level) and site data, plus the references in which the parasite records occur. The host-parasite list is arranged according to the classification of the hosts. In all, c.370 host-parasite associations are recorded, involving 114 nominal species of helminths from 92 named chiropteran taxa.
The complete life cycle of the trematode Ascocotyle (Phagicola) longa (Digenea: Heterophyidae) is elucidated by natural observation validated by experimental infections. The natural first intermediate host of A. (P.) longa, an agent of human heterophyiasis in Brazil, is the cochliopid snail Heleobia australis (new first intermediate host). Metacercariae were found encysted in the body musculature, heart, stomach, liver, kidney, spleen, gonads and mesentery of mullets Mugil liza. Hamsters Mesocricetus auratus were experimentally infected with metacercariae of A. (P.) longa obtained from the mullets, and the adults recovered were used to infect the snails H. australis. Rediae and cercariae of A. (P.) longa are described for the first time. The ultrastructure of the tegument of A. (P.) longa shows a change in spination pattern from the cercaria with single-pointed spines to the metacercaria and adult with multipointed, brush-shaped spines. The life cycle of A. (P.) longa is related to estuaries and coastal lagoons where the recruitment of mugilid juveniles occurs. The high prevalence (100%) of A. (P.) longa encysted in the mullets examined within the urban area of Rio de Janeiro indicates the potentially great public health impact of the consumption of raw mullets.
Viability of Cryptocotyle lingua metacercariae from Atlantic cod (Gadus morhua) after exposure to freezing and heating in the temperature range from -80 °C til 100 °C. Food Control, 50, Viability of Cryptocotyle lingua metacercariae from Atlantic cod (Gadus morhua) after exposure to freezing and heating in the temperature range from À80 C to 100 C a b s t r a c tThe presence of parasites in fish products is a problem that concerns consumers and authorities due to the potential hazards it may cause. The majority of studies on the viability of parasites in marine fish products currently focus on nematodes of the family Anisakidae whereas only few are concerned with trematodes. In this study on the heterophyid trematode Cryptocotyle lingua (identified by morphometric and molecular techniques) we isolated metacercariae from Atlantic cod (Gadus morhua) and incubated the parasites in cod muscle tissue at different temperatures ranging from À80 C to 100 C and subsequently tested their viability. SEM images were made to assess the physical damage caused to parasites exposed to different temperatures. Temperatures between 50 C and 100 C and between À80 C and À20 C killed the metacercariae present in fish flesh in less than 2 h. Controls kept at 5 C survived for nine days. Extreme freezing temperatures caused minimal visual physical damage to cysts, but the tegument of metacercariae was severely affected at all temperatures when incubated for long periods.
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