Multispecies and multiple anthelmintic resistance on cattle nematodes in a farm in Argentina: the beginning of high resistance?

There are very few resistance records on cattle nematodes. South American successive records have been increasing rapidly since the year 2000. In Argentina, increasing dissatisfaction based on the exclusive use of macrocyclic lactones has prompted the use of benzimidazoles in the Pampean region. The studied farm is located in the Argentina humid Pampas and had apparently poor results after anthelmintic treatments. Evaluation of resistance was firstly based on faecal egg reduction after treatment in November 2001 and June 2002 and was complemented with worm counts obtained by necropsy in June 2002. The study reports that the reduction of faecal egg excretion after benzimidazole (reduction 31-79%) or ivermectin treatments (76-97%) in November 2001 was insufficient and these poor results were confirmed in June 2002 (benzimidazoles (65-89%) and ivermectin (47-77%)). Several methods for evaluating faecal egg count reduction were performed and yielded different results. A new method based on the estimated faecal egg counts (corrected from the initial faecal egg counts and animal type using a general linear model) was used and gave higher flexibility in the interpretation of putative resistance to anthelmintics. From necropsy results, it could be concluded that Cooperia oncophora was resistant to avermectins and benzimidazoles and that Cooperia punctata, Ostertagia ostertagi and Haemonchus placei were resistant to benzimidazoles. This case of multispecies and multidrug resistance is probably not unique and could reflect the emergence of resistances in Argentina. This emergence is probably due to the intensive use of anthelmintics, the absence of refugia, and the frequent circulation of infected cattle.     

Evaluation of a specific immunochemotherapy for the treatment of canine visceral leishmaniasis

The efficacy of specific immunochemotherapy against Leishmania infantum infection in dog was studied. The effects on transmission of the disease, as well as the cellular and humoral immune response were examined. The treated animals showed a significant reduction in the infection rates that were detected in Phlebotomus perniciosus females fed on the dog. The humoral immune response, assayed with an indirect immunofluorescence antibody test (IFAT), did not show significant variations under the influence of the therapy. The characterisation of the peripheral blood mononuclear cells (PBMC) using flow cytometry indicated a significant increase in the proportion of T lymphocytes, especially of CD4/TcR(alpha)(beta)(+) and CD4/CD45RA(+) cells, without showing evidence for modifications in the other leukocyte subsets. Cellular lymphoproliferation studies indicated a lack of a specific response to soluble leishmanial antigen (SLA), but the non-specific lymphoproliferative capacity assayed with phytohemagglutinin (PHA) was maintained.     

Goat paratuberculosis in Chile: first isolation and confirmation of Mycobacterium avium subspecies paratuberculosis infection in a dairy goat.

In October 2004, 41 goats > 2 years old from a Saanen dairy goat herd located in Purranque County, 10th Region, Chile, were sampled and tested for paratuberculosis. While collecting samples it was observed that several goats were thin and emaciated. One goat was sufficiently debilitated to warrant humane euthanasia. This animal was brought to the Veterinary School at the Universidad Austral de Chile for necropsy. The goat selected for necropsy was a 12-year-old doe. The animal showed classical clinical signs of caprine paratuberculosis: emaciation despite willingness to eat, dry and rough hair coat, and no evidence of diarrhea. Gross pathology and histopathology of the necropsied goat were consistent with paucibacillary paratuberculosis. Bacteriology, serology, and PCR confirmed the diagnosis. This is the first published report of goat paratuberculosis in Chile confirming a case of caprine paucibacillary paratuberculosis.     

Diagnosis of paratuberculosis by fecal culture and ELISA on milk and serum samples in two types of Chilean dairy goat herds.

Fecal culture has been the primary method used to diagnose paratuberculosis in goats. It is laborious, slow, and expensive. Validation of enzyme-linked immunosorbent assays (ELISAs) on milk samples could make paratuberculosis testing more widely available for goat farmers. The aim of this study was to determine the accuracy of serum and milk ELISAs for paratuberculosis, relative to fecal culture, in Chilean dairy goats. Eight dairy goat herds were selected. Feces, blood, and milk samples were collected from all female goats >2 years old. Fecal samples were cultured using Herrold egg yolk medium with mycobactin J and antibiotics. Serum and milk samples were tested using a commercial ELISA kit for Mycobacterium avium subsp. paratuberculosis antibody detection. A total of 383 goats were tested by ELISA and fecal culture. The sensitivity of ELISA on serum and milk relative to fecal culture was 74.3% (95% CI: 59.8-88.8) and 60% (95% CI: 43.8-76.2), respectively. The corresponding values for ELISA specificity based on the percentage of non- M. avium subsp. paratuberculosis-infected goats testing ELISA-negative were 98.6% (95% CI: 96.6-100) and 99.3% (95% CI: 97.9-100) on serum and milk, respectively. Proportions of positive results for serum and fecal samples were significantly different, whereas the proportions of positive results for milk and fecal samples were not significantly different. The milk ELISA had a moderate level of agreement with fecal culture results (Kappa = 0.57). The paratuberculosis ELISA on goat milk samples may be a cost-effective, accurate alternative to fecal culture.     

Comparative study of the characteristics of the carcass and the meat of the Chato Murciano pig and its cross with Iberian pig, reared indoors

The Chato Murciano pig is a breed catalogued as a Special Protection breed in danger of extinction. At present it is commonly reared in an intensive system. We have studied the mineral composition and other characteristics of its carcass and meat. Samples from the Musculus longissimus lumborum were taken from a total number of 43 animals, divided into two groups, Chato Murciano and Chato Murciano crossed with Iberian, reared in a conventional indoor system. The resulting meat of the Chato Murciano pig and its cross with Iberian was especially rich in iron and copper, rich in phosphorus, and marginally poor in calcium and sodium. The evolution of the pH of the carcass was that of pigs which do not produce PSE (pale, soft and exudative) meat. Some relevant positive correlation coefficients between minerals (P ≤ 0.05) have been found.     

Improvements in somatic embryogenesis protocol in Feijoa (Acca sellowiana (Berg) Burret): Induction,conversion and synthetic seeds

Pineapple guava (Acca sellowiana) syn. Feijoa sellowiana, a Brazilian indigenous Myrtaceae is under domestication in South Brazil. Previous works showed that this species is responsive to somatic embryogenesis and recalcitrant to conventional methods of clonal propagation. In the present work it was evaluated the role of components of culture medium in the induction and development of somatic embryos. The technology of synthetic seeds was also evaluated. Zygotic embryos were inoculated in LPm medium supplemented with 8 mM glutamic acid and 8 mM l-glutamine, 2,4-dichlophenoxiacetic acid (20 μM) and myo-inositol. For conversion of somatic embryos and synthetic seeds it was tested the effect of 6-benzylaminopurine and gibberellic acid combined or not with activated charcoal. The highest values for embryogenetic induction (100%) and number of somatic embryos/explant (113) were observed in the LPm medium supplemented with Glu (8 mM), and 2,4-D. The culture medium supplemented with BA (0.5 μM) and GA₃ (1 μM) and activated charcoal (1.5 g L⁻¹) enhanced the conversion of somatic embryos to plantlets. Pre-germinated somatic embryos encapsulated in sodium alginate with BA (0.5 μM) and GA₃ (1 μM) developed radicles. The use of synthetic seed was a requisite for the survival of plantlets.     

Advances and Perspectives in the Biological Control of Greenhouse Pests with Special Reference to Colombia

This paper analyses the state of the art of biological control of greenhouse pests with special reference to Colombia, one of the world's largest producers of cut flowers. After a discussion of the use and impacts of selected natural enemies on a variety of arthropod pests in greenhouses, suggestions on how to enhance the effectiveness of inundative release strategies further to achieve successful biological control of key pests are provided.     

Blood and haemoglobin meal as protein sources in diets for gilthead sea bream (Sparus aurata): effects on growth, nutritive efficiency and fillet sensory differences

Two parallel experiments were conducted to evaluate the effect of partial substitution of fish meal by two different animal protein sources, blood meal (B) and haemoglobin meal (H) at 0, 50 and 100 g kg⁻¹ of level inclusion in diets for gilthead sea bream, considering a long feeding period for juveniles (Trial 1) and a short feeding period (Trial 2) for on-growing fish. In Trial 1, 33 g juveniles were fed for 242 days and the fish fed with 5% and 10% of haemoglobin dietary inclusion obtained less growth, although feed efficiency, protein efficiency ratio and muscle composition were similar in all diets. In Trial 2, 179 g initial weight fish were fed for 164 days and growth of fish fed H10 showed the lowest growth, although nutrient efficiency and muscle composition were not affected significantly. The results of these experiments demonstrated that blood meal can substitute fish meal (up to 10%) with no effect on performance, but may lead to sensory differences compared with fish fed diet 0, while the inclusion of 5% blood meal had no effect on growth or sensory characteristics. Fish fed 10% haemoglobin inclusion had the poorest growth values.