New parasitological findings for pre-Hispanic camelids.

Paleoparasitological examination provides information of parasite-host associations in the past, shedding light on the geographical origin of some parasites, on the possible dispersal routes and on some of the processes that modelled the parasitic communities. The aim of the present study was to examine parasite remains present in camelid coprolites collected from the archaeological site Alero Destacamento Guardaparque, Patagonia and to discuss the paleoparasitological findings in a biogeographical and paleoecological context. Coprolites were collected from different stratified layers dating from middle to late Holocene, a period covering approximately 7000 years. Paleoparasitological examination revealed the presence of eggs attributed to Lamanema chavezi or Nematodirus lamae, Nematodirus spathiger, Dictyocaulus sp., eggs of two unidentified capillariids, Strongylus-type eggs and oocysts of Eimeria macusaniensis. Enteric parasites of camelids had not changed significantly during the Holocene up to the entry of introduced livestock, although environmental conditions fluctuated greatly throughout this period, indicating the stability of these associations over time. This is the first finding of N. spathiger and Dictyocaulus sp. in paleoparasitological record and their presence are associated with the interaction of camelids with introduced livestock, which likely allowed parasite host switching. In the present study, the zoonotic importance of parasites of camelids is also discussed.

Biometric identification of capillariid eggs from archaeological sites in Patagonia.

Numerous eggs of capillariid nematodes have been found in coprolites from a wide range of hosts and in raptor pellets in archaeological samples from Patagonia. The structure and sculpture of the eggshell of these nematodes and their biometry are commonly used for identification. The aim of this study was to determine whether eggs of the genus Calodium with similar morphology, found in different archaeological samples from Patagonia, belong to the same species. For this purpose, capillariid eggs (N= 843) with thick walls and radial striations were studied by permutational multivariate analysis of variance (PERMANOVA). Eggs exhibiting similar shape and structure also showed similar biometry, regardless of the zoological origin of coprolites (P= 0.84), host diet (P= 0.19), character of the archaeological sites (P= 0.67) and chronology (P= 0.66). Thus, they were attributed to the same species. We suggest that an unidentified zoonotic species of the genus Calodium occurred in the digestive tract of a wide range of hosts in Patagonia during the Holocene and that both human and animal populations were exposed to this parasite during the Holocene in the study area.

Paleoparasitological finding of eggs of nematodes in rodent coprolites dated at the early Holocene from the archaeological site Cerro Casa de Piedra 7, Santa Cruz, Argentina.

The aim of the present study was to examine the parasite remains present in rodent coprolites collected from the archaeological site Cerro Casa de Piedra 7 (CCP7), located in the Perito Moreno National Park (47°57'S, 72°05'W), Santa Cruz Province, Argentina. Eight coprolites obtained from the layer 17, dated at 10,620 ± 40 to 9,390 ± 40 yr B.P., were examined for parasites. Feces were processed whole, rehydrated, homogenized, subjected to spontaneous sedimentation, and examined via light microscopy. Eggs of parasites were measured and photographed. Seven of 8 coprolites possessed 199 eggs of 2, probably new, species of nematodes, including 43 eggs of Heteroxynema sp. Hall, 1916 (Cavioxyura sp. Quentin, 1975) (Oxyurida, Heteroxynematidae), and 156 eggs of Trichuris sp. Roederer, 1761 (Trichinellida, Trichuridae). Heteroxynema sp. is cited for the first time from ancient material worldwide. The finding of Trichuris spp. in both rodents and other host samples from the area under study is indicative of the stability of the biological and environmental conditions for this nematode genus to establish in the Patagonian Early Holocene. The rodent host was assigned to an unknown species of Caviomorpha (Hystricognathi) that lived during the Pleistocenic transition in Patagonia.

First paleoparasitological results from late Holocene in Patagonian coprolites.

These are the first paleoparasitological results from the Late Holocene in Patagonian coprolites. Coprolites collected from layers dated at 3,480 and 2,740 yr before present (B.P.), from the archaeological site Cerro Casa de Piedra, were examined. The site is a hill located in a forest steppe ecotone in Perito Moreno National Park. The coprolites could belong to humans or to other carnivores such as canids. After rehydration and spontaneous sedimentation of the samples, the parasite contents were examined. Results obtained showed the common presence of eggs of a Calodium sp., eggs of other capillariids and trichostrongylids, oocysts of Eimeria macusaniensis (Apicomplexa), and eggs of taeniids (Cestoda). Although the generic identification of some parasites could not be provided, the presence of tapeworm eggs represents the first record for the Late Holocene in Patagonia and shows that parasitism by cestodes existed in the region in pre-Columbian times. Results indicate that in the Late Patagonic Holocene, zoonotic helminths may have been commonly present in the inhabitants of Patagonia. The parasites found in the coprolites allow us to deduce what these people were eating and, thus, indicate what other pathogens, such as viruses, bacteria, and parasitic protozoans, may have infected them via the same sources.

Eimeriid oocysts from archaeological samples in Patagonia, Argentina.

Oocysts attributable to E. macusaniensis Guerrero et al. 1971, were found in coprolites and in archaeological sediments dating to the Holocene of Patagonia, Argentina. By means of a non-parametric regression using a generalized additive model, a significant relationship was found between the size of the oocysts and their antiquity. Specifically, a reduction in oocyst size over time was discovered, probably due to a parasite response to host replacement, to an extinct eimeriid species common during the Pliestocene-Holocene transition, or to environmental changes known for the Holocene. Explanations regarding coevolution between parasites, hosts and paleoenvironmental conditions are discussed herein.

Paleoparasitological analysis of a raptor pellet from southern Patagonia.

Organic remains attributable to one regurgitated pellet were examined. The pellet, belonging to a bird of prey and collected from a cave of Southern Patagonia, was dated at 6,540 +/- 110 yr. With standard paleoparasitological procedures, eggs of Capillaria sp. and a mite, Demodex sp., were found. The parasites found in the pellet belong to a rodent ingested by the bird. The present report constitutes the first paleoparasitological study of a regurgitated pellet.

Paleoparasitological records in a canid coprolite from Patagonia, Argentina.

In this note, organic remains identified as a canid coprolite were examined. The material was dated at 6540 +/- 110 B.P.; it was collected in the Perito Moreno National Park, Santa Cruz, Argentina. Paleoparasitological analysis was performed following standard procedures. Coprolite fragments were rehydrated in a trisodium phosphate aqueous solution and subjected to spontaneous sedimentation for microscope analysis. Eggs of nematodes identified as Trichuris sp., Capillaria sp., Uncinaria sp., and an ascaridid (probably Toxascaris sp.) or spirurids (presumably Physaloptera sp.), plus a cestode (Anoplocephalidae), presumably Moniezia sp., were found.

Redescription of Ichthyofilaria argentinensis Incorvaia, 1999 (Nematoda: Philometridae) parasite of Merluccius hubbsi (Pisces: Merlucciidae) from Argentina.

Ichthyofilaria argentinensis Incorvaia, 1999 (Nematoda: Philometridae) is redescribed from type specimens and from parasites collected from the swim bladder of Argentine hakes Merluccius hubbsi Marini, 1933 caught at the Gulf of San Jorge (46 degrees 30'S, 66 degrees 30'W), Argentine Sea, in July, 1998. Sixteen out of 80 hakes (20%) were found to be parasitised by gravid females of this philometrid. After revision of both these nematodes and type material, the following differences from the original description of the species were observed: (a) cuticle with fine transverse striations, instead of smooth cuticle; (b) presence of cephalic papillae and a pair of amphids; (c) absence of swellings in the oesophagus; (d) oesophageal gland appendix very large and lobulate rather than small and vermiform, and (d) presence of vulva and vagina. The morphological features given in the redescription allow the confirmation of the identity of I. argentinensis as a valid species and to distinguish it from other members of the genus.

Two new Aggregata species (Apicomplexa: Aggregatidae) infecting Octopus tehuelchus and Enteroctopus megalocyathus (Mollusca: Octopodidae) in Patagonia, Argentina.

During a long-term study carried out between 1981 and 1996 on the biological and fishery aspects of octopuses inhabiting the Gulfs of San Matías, San José, and Nuevo, Patagonia, Argentina, 2 new species of Aggregata (Apicomplexa: Aggregatidae) were found in the digestive tracts of Octopus tehuelchus d'Orbigny, 1834 (prevalence 72%) and Enteroctopus megalocyathus (Gould, 1852) (prevalence 77%). Both species can be distinguished from other congeners on the basis of their hosts, the diameters of sporocysts, and number and length of sporozoites. Despite overlap in the distributions of the two hosts species in the area covered in this study, both Aggregata new species exhibited high host specificity.

Digenetic trematodes parasitic on Engraulis anchoita (Pisces: Engraulidae) from Argentina and Uruguay.

A total of 2,086 specimens of Engraulis anchoita Hubbs et Marini (Pisces: Engraulidae), from waters off Argentina and Uruguay were examined for parasitic digeneans. Four species of digeneans were found, Parahemiurus merus (Linton, 1910) (adult) in the stomach; Lecithochirium microstomum Chandler, 1935 (non-ovigerous and ovigerous juveniles) in the swimbladder; Cardiocephaloides sp. (metacercaria) in the eyes and Rhipidocotyle sp. (metacercaria) in the musculature. These four species are recorded for the first time as parasites of E. anchoita.

Mazocraeid monogeneans parasitic on Engraulid fishes in the southwest Atlantic.

Two species of mazocraeid monogeneans are reported for the first time from Argentinean-Uruguayan engraulid fish hosts, Engraulis anchoita and Anchoa marini. Mazocraes australis n. sp. collected from the gills of E. anchoita is described: this new species can be distinguished from the other congenerics by the number of genital hooks in the copulatory organ, the relative size of clamps, and the number of hooks in the terminal lappet. Pseudanthocotyloides heterocotyle found in the gills of E. anchoita and A. marini is redescribed. The diagnosis of both mazocraeid genera are also emended.

Larvae and adults of Hysterothylacium aduncum (Rudolphi, 1802) (Nematoda: Anisakidae) in fishes and crustaceans in the south west Atlantic.

Hysterothylacium aduncum (Rudolphi, 1802) is reported from five fishes and one invertebrate species. Third-stage larvae were found in the crustacean Themisto gaudichaudii and in mesenteries of the fishes Engraulis anchoita and Merluccius hubbsi; fourth-stage larvae were recovered from the digestive tract of M. hubbsi and Scomber japonicus and adult specimens were obtained from the stomach and intestine of M. hubbsi, S. japonicus, Genypterus blacodes and Genypterus brasiliensis. Nematodes are described, measured and illustrated. Parasitic prevalence, mean intensity and range were calculated in relation to different geographic zones, from the Argentinean-Uruguayan Common Fishing Zone to Patagonic areas. An increase of parasitism from the northern areas southwards was observed. The life-cycle of H. aduncum, involving the host species considered, is also postulated.

Myxosporeans and coccidians parasitic on engraulid fishes from the coasts of Argentina and Uruguay.

Two new species of the genus Sphaeromyxa (Myxosporea) from the gall bladder and one new species of the genus Eimeria (Coccidia) parasitizing the testes, are reported from engraulid fishes from the Argentinian shelf (including the Argentinean-Uruguayan Common Fishing Zone): Sphaeromyxa bonaerensis n. sp., found in Engraulis anchoita Hubbs & Marini, 1935 (argentine anchovy) (prevalence 0.2%) and in Anchoa marini Hildebrand, 1943 (anchovy) (prevalence 24.2%) caught in the Bonaerense region of the Argentinian Sea; Sphaeromyxa argentinensis n. sp. found in E. anchoita from all the sampled localities between 34 degrees S and 46 degrees S (prevalence 26.8%) and from A. marini at Mar del Plata coastal zone (prevalence 1.01%). Eimeria patagonensis n. sp. was found in E. anchoita living in the Patagonian region of the Argentine Sea (prevalence 0.45%). Details of some ultrastructural features of S. argentinensis are provided.

Clarification of the identity of copepods of the genus Chondracanthus parasitizing Merluccius hubbsi from Argentinean waters.

In an attempt to clarify the number and identity of copepod species of the genus Chondracanthus Delaroche, 1811 parasitizing common hake Merluccius hubbsi Marini, 1933 from Argentinean waters, a total of 4,569 fish were examined. All of the 995 copepods of the genus Chondracanthus collected from hake showed identical morphology and were identified as Chondracanthus australis Ho, 1991. This species was detected on fish longer than 15 cm of total length and showed an increase in both prevalence and mean intensity in relation to the increase in the size of the host. The highest prevalence and mean intensity were 53.55% and 2.51, respectively. According to our results that coincide with those of other investigators, C. australis seem to be the only species of this genus harbored by M. hubbsi from Argentinean waters.

Some ecological aspects of the copepod parasites of the common hake, Merluccius hubbsi, from the Argentine-Uruguayan coasts.

A total of 2164 common hake Merluccius hubbsi captured in the Argentine-Uruguayan Common Fishing Zone was examined for parasitic copepods. The fish were infested with Chondracanthus palpifer and Neobrachiella insidiosa f. lageniformis, the former parasitizing the buccal cavity and the latter the branchial arches. C. palpifer showed an increase in both prevalence and intensity in relation to the host size; infestation with N. insidiosa f. lageniformis decreased with increasing length of hake. Attachment site preferences and variations in the parasite distribution patterns as related to the host biology were observed. Evidence of negative association between copepod species and seasonal changes in the parasite composition was also found.