Molecular method for the semiquantitative identification of gastrointestinal nematodes in domestic ruminants.

Standard diagnostic methods currently in use for the identification of helminth infections in ruminants are based on the morphological analysis of immature and adult stages of parasites. This paper describes a method for the semiquantitative identification of nematodes, mainly Trichostrongyloidea, at species-level resolution. The method is based on amplification and fragment analysis followed by minisequencing of the ITS-2 region (internal transcribed spacer 2) of the ribosomal DNA of parasite eggs or larvae. This method allows for the identification of seven genera (Chabertia, Cooperia, Haemonchus, Oesophagostomum, Ostertagia, Teladorsagia, and Trichostrongylus) and 12 species (Chabertia ovina, Cooperia curticei, Cooperia punctata, Cooperia oncophora/Cooperia surnabada, Haemonchus contortus, Haemonchus placei, Haemonchus longistipes, Oesophagostomum asperum, Oesophagostomum radiatum, Ostertagia ostertagi, Trichostrongylus axei, and Trichostrongylus colubriformis) of infectious nematodes of domestic ruminants. The concordance between the morphological and molecular analyses in the detection of genera ranged from 0.84 to 0.99, suggesting the proposed detection method is specific, semiquantitative, less laborious, and highly cost-efficient.

Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

This study aimed to evaluate the variability in the fecal egg count (FEC) and the parasitic burden of naive hair sheep after grazing in nematode infected paddocks. The research was carried out in Tabasco, Mexico, during two periods (August and December). In each period 32 lambs were grazed for one month on African star grass (Cynodon plectostachyus) contaminated with gastrointestinal parasitic nematodes. FEC, packed cell volume (PCV) and body weight (BW) were recorded. Gastrointestinal worms were recovered at necropsy. Data were analyzed with the MIXED procedure of SAS using a model of repeated measurements over time. A higher number of Haemonchus contortus worms was found in December (2814±838) than in August (1166±305). The opposite occurred with Cooperia curticei (2167±393 and 3638±441, respectively). The FEC and correlation coefficient in respect to the worm burden were higher in December (6516 ± 1599, r=0.83, respectively) than in August (4364±771, r=0.44, respectively). A high variability in resistance-susceptibility to gastrointestinal nematodes (GIN) occurred in Katahdin × Pelibuey lambs after grazing.(AU)

Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

This study aimed to evaluate the variability in the fecal egg count (FEC) and the parasitic burden of naive hair sheep after grazing in nematode infected paddocks. The research was carried out in Tabasco, Mexico, during two periods (August and December). In each period 32 lambs were grazed for one month on African star grass (Cynodon plectostachyus) contaminated with gastrointestinal parasitic nematodes. FEC, packed cell volume (PCV) and body weight (BW) were recorded. Gastrointestinal worms were recovered at necropsy. Data were analyzed with the MIXED procedure of SAS using a model of repeated measurements over time. A higher number of Haemonchus contortus worms was found in December (2814±838) than in August (1166±305). The opposite occurred with Cooperia curticei (2167±393 and 3638±441, respectively). The FEC and correlation coefficient in respect to the worm burden were higher in December (6516 ± 1599, r=0.83, respectively) than in August (4364±771, r=0.44, respectively). A high variability in resistance-susceptibility to gastrointestinal nematodes (GIN) occurred in Katahdin × Pelibuey lambs after grazing.

Marcadores fenotípicos para caracterização de caprinos com diferentes níveis de resistência às endoparasitoses gastrintestinais / Phenotypic markers to characterize goats with different levels of resistance to gastrointestinal nematodes

O presente trabalho teve como objetivo de avaliar e caracterizar fenotipicamente caprinos com diferentes níveis de resistência a nematoides gastrintestinais. Em um período de 93 dias, 60 caprinos F2 oriundos do cruzamento de animais ½ Saanen e ½ Anglo-nubiano foram mantidos em uma mesma área de pastagem cultivada irrigada de capim Tanzânia (Panicum maximum Jacq. Cv Tanzânia). A cada sete dias, fezes e sangue foram coletados para contagem de ovos por grama de fezes (OPG), coproculturas, contagem de eosinófilos, determinação de volume globular e proteína plasmática total, respectivamente. No mesmo dia das coletas, os animais foram pesados e avaliados quanto ao escore da condição corporal e grau de anemia com auxílio no cartão FAMACHA. Com base na média de OPG, os doze animais com as maiores médias de OPG (grupo susceptível) e os doze animais com as menores médias de OPG (grupo resistente) foram identificados e selecionados para serem abatidos e necropsiados para a recuperação, contagem e identificação dos parasitos presentes. Os animais pertencentes ao grupo resistente apresentaram menor média de OPG (P<0,0001) e 4,7 vezes menos parasitos adultos do que os animais do grupo susceptível. O grupo resistente obteve maior média de volume globular (26,48%) e proteína plasmática total (6,24 g/dl) do que os animais susceptíveis (24,04% e 5,82g/dl, respectivamente). A média de eosinófilos foi semelhante nos dois grupos .O gênero Haemonchus foi o mais prevalente a nas coproculturas, seguido por Trischostrongylus e Oesophagostomum. A contagem de nematoides foi maior no abomaso do grupo susceptível do que no grupo resistente. As espécies identificadas foram H. contortus no abomaso e T. colubriformis no intestino delgado. Conclui-se que OPG, volume globular e proteína plasmática total foram marcadores fenotípicos eficientes para identificar animais resistentes e susceptíveis às infecções causadas por nematoides gastrintestinais.

The aim of this study was to evaluate and character ize phenotypically goats with different levels of resistance to gastro intestinal nematodes. For a period of 93 days, 60 F2 goats originated from ½ Saanen and ½ An glo- nubian animals were kept in the same area of pasture. Every seven days, fece s and blood were collected for eggs per gram counts of feces (EPG) and cultures of fece s and to determinate the number of eosinophils, packed cell volume and total plasma pr otein, respectively. On the same day, the animals were weighed and submitted to body score condition and FAMACHA method to worm control. Based on the average of EPG , the twelve animals with the highest average (susceptible group) and the twelve animals with the lowest average of EPG (resistant group) were selected, slaughtered an d necropsied to recovery, counting andparasites identification. The resistant animals present lower EPG mean (P <0.0001) and 4.7 folder less parasites than susceptible animals. The resistant group presented higher mean packed cell volume (26. 48%) and total plasma protein (6.24 g / dl) than susceptible one (24,04% e 5,82g/ dl, respectively). The average number of eosinophils was similar in both groups The Haemonchus sp. was the most prevalent in the culture of feces, followed by Trischostrongylus sp. and Oesophagostomum sp.. The counting of nematodes in the abomasum of s usceptible group was higher than in resistant one. The species identified were H. contortus in abomasums and T. colubriformis in small intestine. It can be concluded that EPG, packed cell volume and total plasma protein were useful phenoty pic markers to identify animals as resistant and susceptible to gastrointestinal nemat odes infections.

Efeito antagônico de fungos predadores dos gêneros Monacrosporium, Arthrobotrys e Duddingtonia sobre larvas infectantes de Cooperia sp. e Oesophagostomum sp. / Antagonistic effect of nematophagous fungi Monacrosporium, Arthrobotrys and Duddingtonia on infective Cooperia sp. and Oesophagostomum sp. larvae

Seis isolados dos fungos nematófagos Monacrosporium thaumasium (isolado NF 34A), Monacrosporium sinense (isolado SF 470), Monacrosporium appendiculatum (isolado CGI), Arthrobotrys robusta (isolado I 31), Arthrobotrys cladodes (isolado CG 719) e Duddingtonia flagrans (isolado CG 768) foram avaliados em laboratório quanto à capacidade de predar larvas infectantes de Cooperia sp. e Oesophagostomum sp. Nos testes in vitro, os fungos foram eficientes em predar os nematóides (P<0,05), e não houve variação na capacidade predatória entre os fungos testados (P>0,05) durante os cinco dias do ensaio. Estruturas reprodutivas (conídios) foram encontradas em todos os isolados no quinto dia. Todos os fungos testados são promissores para serem utilizados no controle biológico de Cooperia sp. e Oesophagostomum sp., parasitos de bovinos.(AU)

Six isolates of nematophagous fungi Monacrosporium thaumasium (isolate NF 34A), Monacrosporium sinense (isolate SF 470), Monacrosporium appendiculatum (isolate CGI), Arthrobotrys robusta (isolate I 31), Arthrobotrys cladodes (isolate CG 719) and Duddingtonia flagrans (isolate CG 768) were evaluated under laboratory conditions regarding the capacity to entrap infective Cooperia sp. and Oesophagostomum sp. larvae. In the in vitro tests the fungi tested were equally efficient to prey the nematodes (P<0.05) during the five days of the experiment. Reproductive structures (conidia) from all isolates were visualized in 5th day. All fungal isolates were efficient in the control of bovine Cooperia sp. and Oesophagostomum sp. parasites.(AU)

Efeito antagônico de fungos predadores dos gêneros Monacrosporium, Arthrobotrys e Duddingtonia sobre larvas infectantes de Cooperia sp. e Oesophagostomum sp. / Antagonistic effect of nematophagous fungi Monacrosporium, Arthrobotrys and Duddingtonia on infective Cooperia sp. and Oesophagostomum sp. larvae

Seis isolados dos fungos nematófagos Monacrosporium thaumasium (isolado NF 34A), Monacrosporium sinense (isolado SF 470), Monacrosporium appendiculatum (isolado CGI), Arthrobotrys robusta (isolado I 31), Arthrobotrys cladodes (isolado CG 719) e Duddingtonia flagrans (isolado CG 768) foram avaliados em laboratório quanto à capacidade de predar larvas infectantes de Cooperia sp. e Oesophagostomum sp. Nos testes in vitro, os fungos foram eficientes em predar os nematóides (P<0,05), e não houve variação na capacidade predatória entre os fungos testados (P>0,05) durante os cinco dias do ensaio. Estruturas reprodutivas (conídios) foram encontradas em todos os isolados no quinto dia. Todos os fungos testados são promissores para serem utilizados no controle biológico de Cooperia sp. e Oesophagostomum sp., parasitos de bovinos.

Six isolates of nematophagous fungi Monacrosporium thaumasium (isolate NF 34A), Monacrosporium sinense (isolate SF 470), Monacrosporium appendiculatum (isolate CGI), Arthrobotrys robusta (isolate I 31), Arthrobotrys cladodes (isolate CG 719) and Duddingtonia flagrans (isolate CG 768) were evaluated under laboratory conditions regarding the capacity to entrap infective Cooperia sp. and Oesophagostomum sp. larvae. In the in vitro tests the fungi tested were equally efficient to prey the nematodes (P<0.05) during the five days of the experiment. Reproductive structures (conidia) from all isolates were visualized in 5th day. All fungal isolates were efficient in the control of bovine Cooperia sp. and Oesophagostomum sp. parasites.

Estudo clínico, cirúrgico e anatomopatológico de intussuscepção em quatro bovinos / Clinical, surgical, and anatomopathologic study of four intussusception cases in cattle

Descrevem-se os achados clínico, cirúrgico e anatomopatológico de intussuscepção em quatro bovinos fêmeas. Observaram-se intussuscepção do jejuno, com obstrução total, em três animais, e intussuscepção do cólon, com obstrução parcial, em um animal. A presença de parasitismo intenso por Oesophagostomum sp. em dois animais sugere a participação desse parasita na gênese da intussuscepção (AU)

The clinical, surgical, and anatomopathologic findings of four cases of intussusception in cattle are described. In three cows it was observed jejunum intussusception with total obstruction, and in one cow, intussusception of the colon with partial obstruction. The presence of massive parasitism by Oesophagostomum sp. in two animals suggests the participation of this parasite in the genesis of the intussusception.(AU)

Herbage density of third-stage larvae of goat strongyles during the dry season in Guadeloupe.

The objective of this study was to determine the main sources of variation in herbage densities of infective third stage larvae of goat strongyles during the marked dry season of 1994 in Guadeloupe (FWI). Herbage samples were collected for L3 density (LD) determination by an accurate method, 4 times at 4-week intervals in 58 paddocks of 21 farms spread out in five regions of the archipel of Guadeloupe. At the same time, FEC of each grazing animal and fecal culture for parasite genus determination according to sex and age were carried out. Stocking rate, dry matter content of soil, and daily climatic data were also recorded. An index of egg development in larvae (IEDL) was calculated as the ratio of LD to the eggs deposed during the 4th, 3rd, and 2nd weeks before sampling. Medians of LD in herbage were 3397, 1853, 1410, and 324 L3/kg DM for all parasites, Haemonchus, Trichostrongylus, and Oesophagostomum, respectively. Date of sampling, region, and irrigation practice in the northern windward region were the main sources of variation in LD and in frequency of each parasite. LD decreased as the dryness lasted, but it remained important (500 L3/kg DM) despite the drought. LD in windward regions were higher than in other regions. The region, the farm, and the paddock were the main sources of variation of IEDL. LD of each parasites were inversely correlated to global radiation recorded 1 to 3 weeks before herbage sampling, but no relation was found with rainfall data. Trichostrongylus frequency in L3 population increased as the dryness lasted. A dryness axis was extracted from environmental variables (climatic data, dry matter of soil, duration of dryness) by a multiple factorial procedure. LD and Haemonchus frequency in L3 population were inversely correlated to dryness axis (p < 0.01). In contrast, Trichostrongylus frequency was positively correlated to the dryness component.