Norma H. Sardella

Parasite communities of Merluccius hubbsi from the Argentinian-Uruguayan common fishing zone

Abstract This study is based on parasitological examinations of 159 specimens of Merluccius hubbsi (common hake) from the Argentinian-Uruguayan common fishing zone between June and December 1993. The examination extended the list of parasite species previously known from this host in the study area to the following taxa: Anthocotyle merluccii van Beneden and Hesse, 1863; Chondracanthus palpifer Wilson, 1912; Neobrachiella insidiosa f. lageniformis Kabata, 1979; Trifur tortuosus Wilson, 1917; cysts of unknown etiology in gills; Corynosoma spp.; Grillotia spp.; Hepatoxylon trichiuri Holten, 1802; Anisakis spp.; Pseudoterranova spp.; Contracaecum spp.; Hysterothylacium spp.; Microsporidium ovoideum Thelohan, 1895; Elytrophalloides oatesi Leiper and Atkinson, 1914; Derogenes varicus Muller, 1784; Clestobothrium crassiceps Rudolphi, 1802; Scolex polymorphus Muller, 1784; Gorgorhynchidae gen. spp.; Aporocotyle argentinensis Smith, 1969; Kudoa rosenbuschi (Gelormini) Szidat, 1966. The prevalence and intensity of infestation were calculated for each parasite species as related to the body size and sex of the host. The distribution pattern of parasites in hake was also analyzed. Parasite communities of hake examined in the present paper comprises one group of parasite species specific at host family, genus or species level, and another belonging to the local fauna. Component and satellite parasite species were also found.

The parasita Fauna of Scomber japonicus Houttuyn, 1782 (Pisces: Scombridae) in two zones of the Argentine Sea

Abstract Between September 1993 and August 1995, parasitological examinations of 173 specimens of Scomber japonicus were made from two areas of the Argentine Sea: Mar del Plata, 37–38 °S ( N = 90) and El Rincon, 39–41 °S ( N = 83). 94.75% of the mackerel harboured 6081 parasites belonging to the following taxa: Kuhnia scombri (Kuhnia, 1829) Sproston, 1945 (Monogenea); Opechona spp.; Nematobothrium spp. (Digenea); Hysterothylacium spp., Anisakis spp., Contracaecum spp. and Pseudoterranova spp. (Nematoda); Scolex pleuronectis Muller, 1788 (Cestoda); Corynosoma australe Johnston, 1937 (Acanthocephala). With the exception of K. scombri , all the parasites are reported for the first time in mackerel from the area under study. C. australe is the first record for this host. Prevalence and abundance of infestation were calculated for each parasite species and for each area. The importance of host sex, body size, diet and fishing area, as related to the level of infestation of each parasite, is also examined. On the basis on a multivariate analysis, detrended correspondence analysis (DECORANA), the quantitative variations in some parasites show the possibility of their use as tags of different ecological conditions of the two geographic areas.

Paleoparasitological Analysis of Rodent Coprolites in Holocenic Samples from Patagonia, Argentina

Abstract The aim of the present study was to examine the parasite fauna present in rodent coprolites collected from Cerro Casa de Piedra (CCP7), located in Perito Moreno National Park (P.N.P.M., 47°57′S and 72°05′W), Santa Cruz Province, Argentina. Eight coprolites obtained from the layer XIII of CCP7, with an antiquity considered as 7,920 ± 130 yr B.P., were examined for parasites. Each coprolite was whole processed, rehydrated, homogenized, spontaneously sedimented, and examined using light microscopy. Eggs of parasites were measured and photographed. All the samples were parasitized by nematodes, with 267 eggs of Trichuris sp., 24 eggs of an aspidoderid, and 3 capillariid eggs. The rodent host was tentatively identified as a species of Ctenomys, the hypogeic rodents endemic to South America. The finding of Paraspidodera in Patagonian samples represents new evidence that strengthens the co-phylogenies between nematodes of this genus and Ctenomys and reinforces the value of parasites as tags in paleoparasitology.

Corynosoma australe Johnston, 1937 and C. cetaceum Johnston & Best, 1942 (Acanthocephala: Polymorphidae) from marine mammals and fishes in Argentinian waters: allozyme markers and taxonomic status

Genetic and morphological studies were carried out on acanthocephalans belonging to Corynosoma Lühe, 1904 and referable to the species C. cetaceum Johnston & Best, 1942 and C. australe Johnston, 1937, which were recovered from both definitive and intermediate hosts in Argentinian waters. The aims were to estimate the level of genetic differentiation between the two taxa at any stage of their life-cycle, to provide genetic (allozyme) markers for their recognition and to analyse the systematic status of both taxa. Acanthocephalans were collected from the stomach and intestine of Arctocephalus australis (Zimmerman), the intestine of Mirounga leonina (Linnaeus) and the stomach of Pontoporia blainvillei Gervais & D’Orbigny (definitive hosts) in Argentinian waters. Alternative alleles at all the 13 enzymatic loci studied were observed for C. australe and C. cetaceum. The specimens from the stomach of both P. blainvillei and A. australis were identified, on the basis of the great number of diagnostic loci found, as C. cetaceum; those from intestine of both A. australis and M. leonina as C. australe. A high level of genetic differentiation (DNei=∞: INei = 0.00) between the two taxa was found, suggesting a generic distinction between the two species. Cystacanths of the two species from the body-cavity of the fish Cynoscion guatucupa (Cuvier) collected from the same geographical area were identified genetically. Morphological patterns, such as the number of hooks and hook rows on the proboscis, the distribution of somatic and genital armature, and other morphometric and meristic differences, in addition to ecological data, enabled the identification of these two species at cystacanth, juvenile and adult stages. However, a number of morphological and morphometric features of the Argentinian material were different to those of C. australe and C. cetaceum described from other regions of the world.

Zoonotic parasites associated with felines from the Patagonian Holocene

Feline coprolites were examined for parasites with the aim of studying ancient infections that occurred in the Patagonian region during the Holocene period. Eggs compatible to Trichuris sp., Calodium sp., Eucoleus sp., Nematodirus sp., Oesophagostomum sp. (Nematoda), Monoecocestus sp. (Cestoda) and Eimeria macusaniensis (Coccidia) were recovered from faecal samples. The results obtained from the analysis provide evidence of consumption by felids of the viscera of both rodents and camelids. This knowledge allows for improved explanations as to the distribution of parasitism and its significance to the health of humans and animals inhabiting the area under study during the Middle Holocene.

LC50 baseline levels of amitraz, coumaphos, fluvalinate and flumethrin in populations of Varroa destructor from Buenos Aires Province, Argentina

Summary This study estimates the LC50 baseline levels for amitraz, coumaphos, fluvalinate, and flumethrin in susceptible Varroa destructor populations in Argentina. Concentration response bioassays were conducted with each acaricide. Laboratory results of lethal concentrations (LC50) were: 0.1 μg/dish for amitraz; 0.29 μg/dish for fluvalinate; 0.34 μg/dish for flumethrin; and 0.57 μg/dish for coumaphos, respectively. All tests guaranteed 100 % bee survival. LC50 references for mite populations susceptible to the most commonly used acaricides were thus established for Argentina, which will aid the establishment of integrated pest management programmes for V. destructor.

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.

A palaeoparasitological analysis of rodent coprolites from the Cueva Huenul 1 archaeological site in Patagonia (Argentina)

The aim of the present study was to examine the parasite fauna present in rodent coprolites collected from Cueva Huenul 1 (CH1), northern Neuquén (Patagonia, Argentina), an archaeological site that provides stratified sequences of archaeological and palaeontological remains dating from the Late Pleistocene/Early Holocene Transition to the Late Holocene period. Twenty rodent coprolites collected from different sedimentary units from the site, with ages ranging from 13.844 ± 75-1.416 ± 37 years BP, were examined for parasites. Each coprolite was processed as a whole: rehydrated, homogenised, spontaneously sedimented and examined using light microscopy. The coprolites and the eggs of any parasites present were described, measured and photographed. In all, 158 parasite eggs were found in 10 coprolites. The faeces were positive for Viscachataenia quadrata Denegri, Dopchiz, Elissondo & Beveridge and Monoecocestus sp. Beddard (Cestoda: Anoplocephalidae) and for Heteroxynema (Cavioxyura) viscaciae Sutton & Hugot (Nematoda: Oxyuridae). The coprolites examined were tentatively attributed to Lagidium viscacia Molina (Mammalia, Rodentia, Caviomorpha, Chinchillidae). The life cycles of these parasites are discussed.

Morphotypes of Varroa destructor collected in Apis mellifera colonies from different geographic locations of Argentina.

Parasites display considerable phenotypic plasticity in life-history traits such as, body size. Varroa destructor is an ectoparasitic mite of the western honey bee Apis mellifera. Several studies have reported that in V. destructor, there is a wide phenotypic plasticity within a population of mites. However, it is unknown if there are morphologic variations in V. destructor populations affecting different A. mellifera populations. A morphometric study of V. destructor populations was conducted to provide information concerned to the relationships among parasite populations found in different geographic locations from A. mellifera colonies of Argentina. The hypothesis tested was different morphotypes of V. destructor populations parasitizing different A. mellifera populations from Argentina exist. A discriminant analysis employing eight morphologic variables revealed that it is possible to differentiate morphotypes of mites in Argentina. However, the level of discrimination detected among mites population varied according to the grouping of mite’s population. Possible causes explaining the morphometric variability in the V. destructor populations were discussed.

A NEW SPECIES OF DICHELYNE (NEMATODA: CUCULLANIDAE) PARASITIZING ACANTHISTIUS BRASILIANUS (PISCES: SERRANIDAE) FROM ARGENTINEAN WATERS

During a parasitological examination of 45 specimens of Acanthisthius brasilianus (Valenciennes, 1828) Jordan et Eigenmann, 1890, from waters off Mar del Plata, Argentina (38°08′S, 57°32′W), several specimens of cucullanid nematodes were collected from the intestines. A new species, Dichelyne (Cucullanellus) szidati n. sp., is described (prevalence 42.2%, mean intensity 2.7). The new species differs from its congeners inhabiting the southwestern Atlantic by the distribution pattern of caudal papillae, particularly the ninth pair, length of the body and spicules, and the position of the intestinal cecum (ventral), the excretory pore (posterior to esophagus), and the deirids (at the level of esophageal posterior end).