Eosinophilic inflammation in lymph nodes of dogs with visceral leishmaniasis.

Eosinophils are traditionally associated with the immune response against helminth parasites. However, several studies have demonstrated that these cells have a role regarding protective immunity in leishmaniasis. Here, we examined the relationship between the presence of eosinophils and parasite load in biopsy samples from dogs, obtained through fine needle puncture and aspiration of lymph nodes. Histological slides containing biopsy material from lymph nodes of dogs with canine visceral leishmaniasis and healthy dogs were used to obtain baseline eosinophil counts. Subsequently, scrapings were taken from slides for DNA extraction and determination of parasite load, using real-time PCR (qRT-PCR). Additionally, production of nitric oxide (NO) and reactive oxygen species (ROS) levels by eosinophils in the peripheral blood of dogs with canine visceral leishmaniasis and healthy dogs was measured. The eosinophil percentage were higher in lymph nodes of infected group, and the parasite load showed a significant negative correlation with the eosinophil count. The production of NO and ROS by eosinophils in the peripheral blood was higher in the dogs with canine visceral leishmaniasis. All the results together suggest that eosinophils may participate in antileishmanial immunity in canine visceral leishmaniasis.

Anthelmintic resistance in sheep gastrointestinal nematodes in the Northwest Region São Paulo State / Resistência anti-helmíntica de nematódeos gastrintestinais de ovinos da região Noroeste do Estado de SãoPaulo

The occurrence of anthelmintic resistance of gastrointestinal nematodes was investigated on 11 sheep farms of the Northwest region of the State of São Paulo. The tested anthelmintics belong to the groups of the benzimidazoles, imidothiazoles, salicylanilides and macrocyclic lactones. The anthelmintic resistance was considered patent when the egg count reduction in feces was less than 90.0%, evaluated between seven and 14 days after the use of the drugs, using the fecal egg count reduction test according to World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.). The identification of the genera of gastrointestinal nematodes resistant to anthelmintics present in the properties studied was verified by larvae cultures. From 10 herds evaluated for the efficacy of moxidectin, five (50.0%) were resistant to it. Six (54.5%) of 11 herds evidenced resistance to the levamisole. Resistance to the closantel was observed in 10 (90.9%) of 11 farms examined. Resistance to the ivermectin and albendazole was detected in all farms and Haemonchus spp. was the most predominant nematode genus. Therefore, we report the existence of multiple anthelmintic resistance in gastrointestinal nematodes of sheep in the Northwest region of the State of São Paulo.(AU)

A ocorrência da resistência anti-helmíntica de nematódeos gastrintestinais foi avaliada em 11 rebanhos ovinos em fazendas da região Noroeste do Estado de São Paulo. Os grupos de anti-helmínticos testados foram os benzimidazóis, imidazotiazóis, salicilanilidas e lactonas macrocíclicas. A resistência antihelmíntica foi considerada patente, quando a redução das contagens de ovos nas fezes foi inferior a 90,0%, averiguada entre sete a 14 dias após a utilização das drogas, empregando-se o teste de redução de contagem de ovos nas fezes preconizado pela World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.), A identificação dos gêneros de nematódeos gastrintestinais resistentes aos anti-helmínticos presentes nas propriedades estudadas foi verificada com a realização de coproculturas. De 10 rebanhos avaliados para a eficácia da moxidectina, cinco (50,0%) apresentaram resistência à mesma. Seis (54,5%) de 11 rebanhos evidenciaram resistência ao levamisol. Resistência ao closantel foi observada em 10 (90,9%) das 11 propriedades examinadas. Resistência a ivermectina e ao albendazol foi detectada em todas as propriedades estudadas. Haemonchus spp. foi o gênero de nematódeo amplamente predominante. Assim, nós relatamos a ocorrência de resistência múltipla anti-helmintíca em nematóides gastrintestinais de ovinos em fazendas da região Noroeste do Estado de São Paulo.(AU)

Anthelmintic resistance in sheep gastrointestinal nematodes in the Northwest Region São Paulo State / Resistência anti-helmíntica de nematódeos gastrintestinais de ovinos da região Noroeste do Estado de SãoPaulo

The occurrence of anthelmintic resistance of gastrointestinal nematodes was investigated on 11 sheep farms of the Northwest region of the State of São Paulo. The tested anthelmintics belong to the groups of the benzimidazoles, imidothiazoles, salicylanilides and macrocyclic lactones. The anthelmintic resistance was considered patent when the egg count reduction in feces was less than 90.0%, evaluated between seven and 14 days after the use of the drugs, using the fecal egg count reduction test according to World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.). The identification of the genera of gastrointestinal nematodes resistant to anthelmintics present in the properties studied was verified by larvae cultures. From 10 herds evaluated for the efficacy of moxidectin, five (50.0%) were resistant to it. Six (54.5%) of 11 herds evidenced resistance to the levamisole. Resistance to the closantel was observed in 10 (90.9%) of 11 farms examined. Resistance to the ivermectin and albendazole was detected in all farms and Haemonchus spp. was the most predominant nematode genus. Therefore, we report the existence of multiple anthelmintic resistance in gastrointestinal nematodes of sheep in the Northwest region of the State of São Paulo.

A ocorrência da resistência anti-helmíntica de nematódeos gastrintestinais foi avaliada em 11 rebanhos ovinos em fazendas da região Noroeste do Estado de São Paulo. Os grupos de anti-helmínticos testados foram os benzimidazóis, imidazotiazóis, salicilanilidas e lactonas macrocíclicas. A resistência antihelmíntica foi considerada patente, quando a redução das contagens de ovos nas fezes foi inferior a 90,0%, averiguada entre sete a 14 dias após a utilização das drogas, empregando-se o teste de redução de contagem de ovos nas fezes preconizado pela World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.), A identificação dos gêneros de nematódeos gastrintestinais resistentes aos anti-helmínticos presentes nas propriedades estudadas foi verificada com a realização de coproculturas. De 10 rebanhos avaliados para a eficácia da moxidectina, cinco (50,0%) apresentaram resistência à mesma. Seis (54,5%) de 11 rebanhos evidenciaram resistência ao levamisol. Resistência ao closantel foi observada em 10 (90,9%) das 11 propriedades examinadas. Resistência a ivermectina e ao albendazol foi detectada em todas as propriedades estudadas. Haemonchus spp. foi o gênero de nematódeo amplamente predominante. Assim, nós relatamos a ocorrência de resistência múltipla anti-helmintíca em nematóides gastrintestinais de ovinos em fazendas da região Noroeste do Estado de São Paulo.

Resistência anti-helmíntica de nematóides gastrintestinais em ovinos, Mato Grosso do Sul / Anthelmintic resistance of gastrointestinal nematodes in sheep, Mato Grosso do Sul, Brazil

Entre os métodos de controle da verminose gastrintestinal em ovinos, a utilização de produtos químicos é o mais empregado. Porém, o uso indiscriminado e continuado desses produtos tem selecionado populações de helmintos resistentes aos anti-helmínticos, fenômeno relatado no mundo todo. Este trabalho teve como objetivo identificar as espécies de parasitos gastrintestinais e diagnosticar a situação da resistência anti-helmíntica em ovinos no Estado de Mato Grosso do Sul. Foram realizados testes de redução na contagem de ovos por grama de fezes (OPG) em rebanhos de dezesseis propriedades rurais; as sete formulações utilizadas continham as seguintes bases farmacológicas: Albendazol, Ivermectina, Levamisole, Triclorfon, Moxidectina, Closantel e uma contendo as três primeiras associadas. As espécies identificadas nas necropsias, em ovinos adultos, foram: Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, C. punctata, C. pectinata e Oesophagostomum columbianum; em ordem de prevalência. As formulações contendo Albendazol e Ivermectina não apresentaram eficácia na redução de OPG nos rebanhos testados, com médias de redução de 0,7 e -19,6 por cento, respectivamente. Closantel apresentou eficácia média de 6,7 por cento; Levamisole, Moxidectina e Triclorfon de 28,7, 26,8 e 65 por cento, respectivamente; a associação das três bases (Albendazol, Ivermectina e Levamisole), uma média de eficácia de 55,8 por cento. As percentagens médias de larvas infectantes recuperadas nas coproculturas, tanto no pré como no pós-tratamento, foram semelhantes; indicando que a resistência às bases testadas está presente em todas as espécies citadas, em maior ou menor intensidade. Os dois gêneros predominantemente resistentes são Haemonchus sp., com 86,9 por cento; seguido por Trichostrongylus sp., com média de 47,5 por cento; Strongyloides sp. 33,6 por cento; Oesophagostomum, sp. 21,4 por cento e Cooperia sp. 19,7 por cento.(AU)

Among the methods of control of gastrointestinal worms in sheep, the use of chemicals is the most common. However, the continued, and indiscriminate, use of these products has selected populations of resistant helminths to anthelmintics, a phenomenon reported in the whole world. This study aimed to identify the species of gastrointestinal parasites and diagnose the status of anthelmintic resistance in sheep in the State of Mato Grosso do Sul Brazil. Feacal egg count reduction tests (FECRT) were performed in flocks of sixteen farms, and the seven formulations used contained the following pharmacological bases: Albendazole, Ivermectin, Levamizol, Trichlorfon, Moxidectin, Closantel and one containing the first three in association. The species identified at necropsy, in adult sheep, were: Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, C. punctata, C. pectinata and Oesophagostomum columbianum, in order of prevalence. The formulations containing Albendazole and Ivermectin did not show efficacy in reducing the EPG in the flocks tested, with average reductions of 0.7 and -19.6 percent, respectively. Closantel presented an average efficacy of 6.7 percent; Levamisolee, Moxidectin and Trichlorfon, 28.7, 26.8 and 65 percent respectively, the combination of three bases (Albendazole, Ivermectin and Levamizol), an average efficacy of 55.8 percent. The average percentages of infective larvae recovered in the faecal cultures, pre and post treatment were similar, indicating that resistance to the bases tested is present in all species cited, to a greater or lesser degree. The two genera predominantly resistant are Haemonchus sp., with 86.9 percent, followed by Trichostrongylus sp., with an average of 47.5 percent, Strongyloides sp. 33.6 percent, Oesophagostomum sp. 21.4 percent and Cooperia sp. 19.7 percent.(AU)

Resistência anti-helmíntica de nematóides gastrintestinais em ovinos, Mato Grosso do Sul / Anthelmintic resistance of gastrointestinal nematodes in sheep, Mato Grosso do Sul, Brazil

Entre os métodos de controle da verminose gastrintestinal em ovinos, a utilização de produtos químicos é o mais empregado. Porém, o uso indiscriminado e continuado desses produtos tem selecionado populações de helmintos resistentes aos anti-helmínticos, fenômeno relatado no mundo todo. Este trabalho teve como objetivo identificar as espécies de parasitos gastrintestinais e diagnosticar a situação da resistência anti-helmíntica em ovinos no Estado de Mato Grosso do Sul. Foram realizados testes de redução na contagem de ovos por grama de fezes (OPG) em rebanhos de dezesseis propriedades rurais; as sete formulações utilizadas continham as seguintes bases farmacológicas: Albendazol, Ivermectina, Levamisole, Triclorfon, Moxidectina, Closantel e uma contendo as três primeiras associadas. As espécies identificadas nas necropsias, em ovinos adultos, foram: Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, C. punctata, C. pectinata e Oesophagostomum columbianum; em ordem de prevalência. As formulações contendo Albendazol e Ivermectina não apresentaram eficácia na redução de OPG nos rebanhos testados, com médias de redução de 0,7 e -19,6 por cento, respectivamente. Closantel apresentou eficácia média de 6,7 por cento; Levamisole, Moxidectina e Triclorfon de 28,7, 26,8 e 65 por cento, respectivamente; a associação das três bases (Albendazol, Ivermectina e Levamisole), uma média de eficácia de 55,8 por cento. As percentagens médias de larvas infectantes recuperadas nas coproculturas, tanto no pré como no pós-tratamento, foram semelhantes; indicando que a resistência às bases testadas está presente em todas as espécies citadas, em maior ou menor intensidade. Os dois gêneros predominantemente resistentes são Haemonchus sp., com 86,9 por cento; seguido por Trichostrongylus sp., com média de 47,5 por cento; Strongyloides sp. 33,6 por cento; Oesophagostomum, sp. 21,4 por cento e Cooperia sp. 19,7 por cento.

Among the methods of control of gastrointestinal worms in sheep, the use of chemicals is the most common. However, the continued, and indiscriminate, use of these products has selected populations of resistant helminths to anthelmintics, a phenomenon reported in the whole world. This study aimed to identify the species of gastrointestinal parasites and diagnose the status of anthelmintic resistance in sheep in the State of Mato Grosso do Sul Brazil. Feacal egg count reduction tests (FECRT) were performed in flocks of sixteen farms, and the seven formulations used contained the following pharmacological bases: Albendazole, Ivermectin, Levamizol, Trichlorfon, Moxidectin, Closantel and one containing the first three in association. The species identified at necropsy, in adult sheep, were: Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, C. punctata, C. pectinata and Oesophagostomum columbianum, in order of prevalence. The formulations containing Albendazole and Ivermectin did not show efficacy in reducing the EPG in the flocks tested, with average reductions of 0.7 and -19.6 percent, respectively. Closantel presented an average efficacy of 6.7 percent; Levamisolee, Moxidectin and Trichlorfon, 28.7, 26.8 and 65 percent respectively, the combination of three bases (Albendazole, Ivermectin and Levamizol), an average efficacy of 55.8 percent. The average percentages of infective larvae recovered in the faecal cultures, pre and post treatment were similar, indicating that resistance to the bases tested is present in all species cited, to a greater or lesser degree. The two genera predominantly resistant are Haemonchus sp., with 86.9 percent, followed by Trichostrongylus sp., with an average of 47.5 percent, Strongyloides sp. 33.6 percent, Oesophagostomum sp. 21.4 percent and Cooperia sp. 19.7 percent.

Diagnóstico da resistência dos nematóides gastrintestinais a anti-helmínticos em rebanhos caprino e ovino do RN / Diagnosis of nematodes gastrintestinal resistance to antihelminthic in goats and sheep from Rio Grande do Norte state, Brazil

O controle dos endoparasitos gastrintestinais em rebanhos de caprinos e ovinos vem sendo realizado através de diversos grupos químicos de anti-helmínticos, sem considerar os fatores epidemiológicos predominantes da região e a realização de esquemas racionais de alternância de drogas. O objetivo do presente trabalho foi avaliar a sensibilidade dos nematóides gastrintestinais a compostos anti-helmínticos no estado do Rio Grande do Norte. Foram utilizados 54 caprinos e 54 ovinos, fêmeas sem padrão racial definidos. Os compostos testados foram albendazol 10% e ivermectina. Para a avaliação da resistência usou-se o teste de redução na contagem de ovos por grama de fezes (RCOF) e coprocultura. Em ovino a RCFO foi: albendazole 44,3%, 54,2% e 70,9%, ivermectina 11,4%, 28,8% e 22,1% em 7, 14 e 21 dias respectivamente. Em caprinos a RCOF foi: para albendazole 2,9%, 9,6% e 24,1%, e para ivermectina 24,9%, 12% e 5,9% em 7, 14 e 21 dias respectivamente. Observou-se que o gênero Haemonchus, foi o mais prevalente na população resistente aos anti-helminticos testados, tanto em ovinos como em caprinos, seguidos de Strongyloides, Trichostrongylus, e Ooesophagostomum.

The gastrointestinal parasites control in goats and sheep flock have been accomplished through several chemical groups of anthelmintics, without considering the predominant epidemic factors of the local and the accomplishment of rational outlines of drugs alternation. The objective of present work was to evaluate the sensibility of the gastrointestinal nematodes in relationship to the anthelminthics within state of Rio Grande do Norte. Therefore, it has been used 54 goats and 54 sheep, females without pattern racial defined. The composts tested were albendazole 10% and ivermectin. For the evaluation of the resistance reduction test it was used the number of eggs per gram of feces (RCOF) and fecal culture. In sheep RCFO was: for albendazole 44,3%, 54,2% and 70,9%, for ivermectin 11,4%, 28,8% and 22,1% at the 7th, 14th and 21st day powder-treatment respectively. In goats RCOF was: for albendazole 2,9%, 9,6% and 24,1%, and for ivermectin 24,9%, 12% and 5,9% at the 7th, 14th and 21st day powder-treatment respectively. Thus, it was observed that the gender Haemonchus was prevalent in the resistant population for the anthelmintics tested in sheep as in goats, followed by Strongyloides, Trichostrongylus, and Oesophagostomum.

Synergistic action of praziquantel and host specific immune response against Schistosoma mansoni at different phases of infection.

The interaction between specific immune response to Schistosoma mansoni and praziquantel (PZQ) was studied in mice. In mice harboring concomitant immunity, 6-day-old parasites treated with PZQ were more effectively removed than 24 h treated parasites despite both had a significant worm burden reduction when compared with respective treated controls. These results show that PZQ can be effective at the skin and lung stages of parasite's development mainly acting with a established specific immune response, and particularly at the lung phase.

Effects of previous suppressive anthelmintic treatments on subsequent nematode infection in fattening cattle in Argentina.

The effect of previous suppressive anthelmintic treatments after weaning on parasitological parameters and weight gain of cattle was studied in the Pampeana region of Argentina. The study was carried out at two grazing fattening periods: April 1995/July 1996 and April 1997/July 1998. During both periods, 60 weaned calves that grazed contaminated pastures, were divided into three groups during the first part of the periods: GY1 group was treated every 2 weeks with doramectin while GY2 and GY3 groups remained untreated. During the second part of the periods, from October onwards GY1 and GY2 remained untreated and GY3 was treated every 2 weeks. In this second period two new groups of 20 weaning young calves were added: TG (treated every 2 weeks) and UG (untreated). Egg counts (EPG), larval cultures, pasture larval counts, serum pepsinogen (Pep) and live weight gain (LWG) were recorded monthly. Ostertagia, Cooperia, Trichostrongylus and Haemonchus were the predominant genera. Despite low levels of previous infection during the first part of the period, slight differences of EPG between GY1 (P<0.09) or UG (P<0.05) and GY2 were detected in the second part of the fattening period in 1995/1996. In 1997/1998 moderate infection levels during the first part of the period were observed. During the second part of this period, GY1 and UG showed higher (P<0.001) EPG than GY2, and only GY3 and TG had (P<0.05) lower Pep levels. Also, during the second part of 1997/1998, LWG responses of GY3 were higher (P<0.001) than those of GY1 and GY2. Live weight gain of GY2 exceeded GY1 by 10.7kg (P<0.006). Higher EPG and lower LWG of GY1 suggest that suppressive treatments negatively affected the level of resistance to infection of yearlings, but these effects were influenced by previous levels of nematode infection. The lack of differences between yearling (GY1) and calves (UG) groups suggest that, under the conditions of this study, there was no evidence that resistance to infection and the related parameters are influenced by the age.