Influence of silvopastoral systems on gastrointestinal nematode infection and immune response of Nellore heifers under tropical conditions.

Among the strategies for integrating crops, livestock, and forestry, silvopastoral systems must be highlighted due to their inherent microclimatic conditions, mainly in tropical countries such as Brazil, where cattle are frequently subjected to unfavorable thermal conditions. However, according to some studies, shading can potentially worsen herds´ parasitism due to better microclimatic condition for the parasites. This study aimed to assess fecal egg count in Nellore heifers reared in two silvopastoral arrangements (pasture with single or triple tree rows), in a crop-livestock system, and open pasture. In the silvopastoral treatment composed of triple rows, lesser parasite burden means were found, with a peak infection in February/March and another in October. Regarding the effect of seasons over the year, there was an environmental influence on the egg counts, with higher averages during the late rainy season and the beginning of the dry season. An immunological investigation of animals from each group showed that cattle kept on the silvopastoral arrangements with either single or triple rows have significantly higher lymphocyte proliferation when stimulated with specific antigens than those kept on open pastures. Based on our results, it can be concluded that both silvopastoral systems were not considered as a risk factor for nematode egg counts in Nellore heifers. Indeed, the shadiest system promoted milder parasitism and higher immunological lymphocyte responses in animals.

Characterisation of Macrophage Polarisation in Mice Infected with Ninoa Strain of Trypanosoma cruzi.

Macrophages (MΦ) play a key role in the development of the protective immune response against Trypanosoma cruzi infection. To determine the role of MΦ subtypes M1 and M2 in the development of immunity against the Mexican strain of T. cruzi (Ninoa strain), we have analysed in a time course the infection and characterised the M1 and M2 subtypes in two mouse models, BALB/c and C57BL/6. After infection, BALB/c mice developed an increased blood parasite load and the parasites were cleared from the blood one week later than in C57BL/6 mice. However, similar cellular infiltrate and cardiac alterations were observed between BALB/c and C57BL/6 mice. At 36 days, the T. cruzi infection differentially modulated the expression of immune cells, and both the BALB/c and C57BL/6 mice significantly reduced TCD4+ cells. However, BALB/c mice produced significantly more TCD8+ than C57BL/6 mice in the spleen and lymph nodes. Furthermore, BALB/c mice produce significantly more MΦ in the spleen, while C57BL/6 produce similar levels to uninfected mice. The M1 MΦ ratio increased significantly at 3-5 days post-infection (dpi), but then decreased slightly. On the contrary, the M2 MΦ were low at the beginning of the infection, but the proportion of M1 and M2 MΦ at 36 dpi was similar. Importantly, the MΦ subtypes M2c and M2d significantly increased the induction of tissue repair by the end of the acute phase of the infection. These results indicate that the Ninoa strain has developed strategies to modulate the immune response, with fine differences depending on the genetic background of the host.

Molecular Identification of Zoonotic Parasites of the Genus Anisakis (Nematoda: Anisakidae) from Fish of the Southeastern Pacific Ocean (Off Peru Coast).

The study aims to perform, for the first time, the molecular identification of anisakid larvae in commercial fish from the Southeastern Pacific Ocean off the Peru coast, and to provide data on their infection level by fishing ground, fish host, and site of infection. Fish specimens (N = 348) from the northern and the central coast of Peru were examined for parasites. The fish fillets were examined by the UV-press method. Anisakis spp. larvae (N = 305) were identified by mtDNA cox2 sequences analysis and by the ARMS-PCR of the locus nas10 nDNA. Two hundred and eighty-eight Anisakis Type I larvae corresponded to Anisakis pegreffii, whereas 17 Anisakis Type II larvae clustered in a phylogenetic lineage distinct from Anisakis physeteris deposited in GenBank, and corresponding to a phylogenetic lineage indicated as Anisakis sp. 2, previously detected in fish from both Pacific and Atlantic waters. Anisakis pegreffii was found to infect both the flesh and viscera, while Anisakis sp. 2 occurred only in the viscera. The average parasitic burden with A. pegreffii in the examined fish species from the two fishing grounds was significantly higher than that observed with Anisakis sp. 2. The results obtained contribute to improve the knowledge on the distribution and occurrence of Anisakis species in Southeastern Pacific waters and their implications in seafood safety for the local human populations.

Effect of deworming on milk production in dairy cattle and buffaloes infected with gastrointestinal parasites in the Kavrepalanchowk district of central Nepal.

BACKGROUND: In Nepal, knowledge of proper handling, management and causes of cattle diseases is still limited. The main objective of this study was to explore the impact of deworming on milk production and its effect on milk qualities. METHODS: A total of 200 faecal samples (100 buffaloes and 100 cows) were collected and analysed for parasitic burden. Half of the infected cattle (buffaloes, Bos bubalis; cow native, B indicus; European, B taurus) were then dewormed with Levamisole Hydrochloride-Oxyclozanide bolus, and the remaining 50 per cent were left untreated. The milk yield from both infected and dewormed cattle was recorded for 30 days and the qualities of milk were analysed. RESULTS: The prevalence of parasitic infection was found to be 22.0 per cent. Fasciola hepatica was the predominant parasite (81.8 per cent), followed by Toxocara vitulorum (34.1 per cent), Strongyloides papillosus (6.8 per cent) and Bunostomum phlebotomum (4.5 per cent). The average milk yield (litre/day/cow) significantly increased, which was 1.22 litres per day for treated cows and 1.06 litres for treated buffaloes. The intervention effect of deworming among cows was 0.79 (14.06 per cent increment) and for buffaloes was 0.42 (8.32 per cent increment). After deworming the infected cattle, the protein percentage was significantly improved in cows (P=0.035), whereas the lactose percentage and solid percentage had increased significantly in buffaloes (P=0.002 and P=0.028). CONCLUSION: Antiparasitic treatment in cattle had positive effects on milk qualities such as solid non-fat, lactose, solid percentage and total protein percentage.

Pro-inflammatory cytokine Interleukin-1ß (IL-1ß) controls Leishmania infection.

Leishmania is an obligate intracellular parasite uses low pH phagolysosomal compartments of host macrophages as their final abode. IL-1ß is a pro inflammatory cytokine, which is secreted by immune cells to trigger inflammation and this has been found profoundly in the lesions caused by Leishmania pathogens. But the specific role of this cytokine on host cell macrophages during infection has not been fully explored. Here in, we have showed that prolonged exposure of IL-1ß on macrophages increases the parasite burden. Pre-treatment of bone marrow derived macrophages (BMDM) with IL-1ß also generates significantly higher amount of anti-inflammatory cytokine IL-10. As IL-10 plays crucial role in the establishment of infection, enhanced production of IL-10 observed upon IL-1ß treatment could contribute to the progression of the disease. By quantifying the production of Nitric oxide (NO), we further report that the pretreatment of IL-1ß fails to produce the nitric oxide. By measuring the footpad thickness in two different mice strains of differential susceptibility we showed IL-1ß treatment increases parasitic burden. As our results shows that the exposure of IL-1ß helps in disease progression, IL-1ß signalling may be an attractive target for future therapeutic intervention.

Parasitic load and histological aspects in different regions of the spleen of dogs with visceral leishmaniasis.

Leishmania infantum causes from subclinical infection to severe disease in humans and dogs. The spleen is one of the organs most affected by the infection. Although evidence exists that the parasitic load distribution and histological alterations may not be homogeneous in the affected organs of naturally infected individuals, it has not been formally demonstrated using the current techniques used for studying the disease. In six dogs naturally infected with Leishmania, parasitic load and histological changes were compared in samples collected from the lower, middle and upper third of the spleen. Parasitic load in the spleen of the group of dogs was variable, revealing a difference of 61 times between animals with the lowest and the highest parasitism. The set of parasitic load values of each dog showed a cluster trend, when compared to the other animals. Nevertheless, the parasitic load values of each dog showed a variation ranging from 3.2 to 34.7 times between lowest and highest value. Histological changes showed recognizable variation in frequency (granulomas) or intensity (perisplenitis) in the spleen of 2 out of the 6 dogs. The agreement of histological findings between samples collected from the different thirds of the spleen was good (kappa coeficient, 0.61-0.80) very good (0.81-0.99) or perfect (1.00), for most of the parameters analyzed. Variability of parasitic load and, to a lesser extent, histological changes in spleen of dogs with visceral leishmaniasis is observed. Such variability may be taken in account in the design of studies on pathogenesis, vaccine and therapeutic drug development.

Detección de Trypanosoma cruzi en tejido y sangre murina por PCR convencional y en tiempo real / Detection of Trypanosoma cruzi in murine blood and tissue by conventional and real time PCR / Detecção de Trypanosoma cruzi em tecido e sangue murinos por PCR convencional e em tempo real

El objetivo del presente trabajo fue comparar la detección de ADN de Trypanosoma cruzi mediante PCR en tiempo real (qPCR) y PCR convencional en sangre periférica (n=25) y músculo esquelético (n=20) de ratones tratados con drogas tripanomicidas luego de 6 meses post-tratamiento. En las muestras de sangre se detectaron un total de 7 positivas por qPCR, mientras que por PCR convencional sólo se detectaron 2. En músculo esquelético, 15 muestras fueron positivas por qPCR y 3 por PCR convencional. Los resultados obtenidos demuestran que la fuerza de concordancia es débil entre las técnicas de PCR utilizadas para la detección de ADN de T. cruzi (k=0,37; 49% positivas por qPCR vs. 11% por PCR convencional, p=0,0001). En las muestras de sangre, los valores diagnósticos de qPCR con respecto a la PCR convencional fueron: 100% sensibilidad; 78% especificidad; 30% VPP; 100% VPN; 4,6 RVP; 0 RVN. Para las muestras de músculo esquelético se obtuvieron los siguientes valores diagnósticos de qPCR: 100% sensibilidad; 29% especificidad; 20% VPP; 100% VPN; 1,4 RVP; 0 RVN. Ambas técnicas fueron igualmente sensibles en el rango de mediana-alta concentración, pero qPCR fue más efectiva para detectar bajas cargas parasitarias, en particular en las muestras de tejido.

The aim of this work was to compare detection of Trypanosoma cruzi DNA by real time (qPCR) and conventional PCR in peripheral blood (n=25), and skeletal muscle (n=20) of mice treated with trypanocidal compounds after 6 months post-treatment. A total of 7 blood samples were positive by qPCR; whereas, by conventional PCR only 2 were detected. In skeletal muscle, 15 samples were regarded positive by qPCR and 3 by conventional PCR. These results showed a weak concordance strength among PCR techniques employed to detect T. cruzi DNA in the studied samples (k=0.37; 49% positives by qPCR vs. 11% by conventional PCR, p=0.0001). In blood samples, qPCR diagnostic values in comparison with conventional PCR were: 100% sensibility; 78% specificity; 30% PPV; 100% NPV; 4.6 PVR; 0 NVR. For skeletal muscle samples, qPCR diagnostic values were: 100% sensibility; 29% specificity; 20% PPV; 100% NPV; 1.4 PVR; 0 NVR. Both techniques were equally sensitive in the medium-high concentration range, but qPCR was more effective to detect low parasitic burden, particularly in skeletal muscle samples.

O objetivo deste estudo foi comparar a detecção de DNA de Trypanosoma cruzi por PCR em tempo real (qPCR) e PCR convencional no sangue periférico (N=25) e músculo esquelético (N= 20) de camundongos tratados com medicamentos tripanomicidas depois de 6 meses de pós-tratamento. Nas amostras de sangue foi detectado um total de sete positivas por qPCR; enquanto que apenas foram encontradas 2 por PCR convencional. No músculo esquelético, 15 amostras foram positivas por qPCR e 3 por PCR convencional. Os resultados mostram que a força de concordância é fraca entre as técnicas de PCR utilizadas para a detecção de DNA de T. cruzi (k=0,37, 49% positivas por qPCR vs. 11% para a PCR convencional, p=0,0001). Nas amostras de sangue, os valores diagnósticos de qPCR em relação a PCR convencional foram de 100% sensibilidade; 78% de especificidade; 30% de VPP; 100% VPN; 4,6 RVP; 0 RVN. Para as amostras de músculo esquelético, os seguintes valores diagnósticos de qPCR foram obtidos: 100% sensibilidade; 29% de especificidade; 20% de VPP; 100% VPN; 1,4 RVP; 0 RVN. Ambas as técnicas são igualmente sensíveis na faixa de concentração média-alta, mas qPCR foi mais eficaz na detecção de baixas cargas parasitárias, especialmente em amostras de tecido.

Detección de Trypanosoma cruzi en tejido y sangre murina por PCR convencional y en tiempo real / Detection of Trypanosoma cruzi in murine blood and tissue by conventional and real time PCR / DetecþÒo de Trypanosoma cruzi em tecido e sangue murinos por PCR convencional e em tempo real

El objetivo del presente trabajo fue comparar la detección de ADN de Trypanosoma cruzi mediante PCR en tiempo real (qPCR) y PCR convencional en sangre periférica (n=25) y músculo esquelético (n=20) de ratones tratados con drogas tripanomicidas luego de 6 meses post-tratamiento. En las muestras de sangre se detectaron un total de 7 positivas por qPCR, mientras que por PCR convencional sólo se detectaron 2. En músculo esquelético, 15 muestras fueron positivas por qPCR y 3 por PCR convencional. Los resultados obtenidos demuestran que la fuerza de concordancia es débil entre las técnicas de PCR utilizadas para la detección de ADN de T. cruzi (k=0,37; 49% positivas por qPCR vs. 11% por PCR convencional, p=0,0001). En las muestras de sangre, los valores diagnósticos de qPCR con respecto a la PCR convencional fueron: 100% sensibilidad; 78% especificidad; 30% VPP; 100% VPN; 4,6 RVP; 0 RVN. Para las muestras de músculo esquelético se obtuvieron los siguientes valores diagnósticos de qPCR: 100% sensibilidad; 29% especificidad; 20% VPP; 100% VPN; 1,4 RVP; 0 RVN. Ambas técnicas fueron igualmente sensibles en el rango de mediana-alta concentración, pero qPCR fue más efectiva para detectar bajas cargas parasitarias, en particular en las muestras de tejido.(AU)

The aim of this work was to compare detection of Trypanosoma cruzi DNA by real time (qPCR) and conventional PCR in peripheral blood (n=25), and skeletal muscle (n=20) of mice treated with trypanocidal compounds after 6 months post-treatment. A total of 7 blood samples were positive by qPCR; whereas, by conventional PCR only 2 were detected. In skeletal muscle, 15 samples were regarded positive by qPCR and 3 by conventional PCR. These results showed a weak concordance strength among PCR techniques employed to detect T. cruzi DNA in the studied samples (k=0.37; 49% positives by qPCR vs. 11% by conventional PCR, p=0.0001). In blood samples, qPCR diagnostic values in comparison with conventional PCR were: 100% sensibility; 78% specificity; 30% PPV; 100% NPV; 4.6 PVR; 0 NVR. For skeletal muscle samples, qPCR diagnostic values were: 100% sensibility; 29% specificity; 20% PPV; 100% NPV; 1.4 PVR; 0 NVR. Both techniques were equally sensitive in the medium-high concentration range, but qPCR was more effective to detect low parasitic burden, particularly in skeletal muscle samples.(AU)

O objetivo deste estudo foi comparar a detecþÒo de DNA de Trypanosoma cruzi por PCR em tempo real (qPCR) e PCR convencional no sangue periférico (N=25) e músculo esquelético (N= 20) de camundongos tratados com medicamentos tripanomicidas depois de 6 meses de pós-tratamento. Nas amostras de sangue foi detectado um total de sete positivas por qPCR; enquanto que apenas foram encontradas 2 por PCR convencional. No músculo esquelético, 15 amostras foram positivas por qPCR e 3 por PCR convencional. Os resultados mostram que a forþa de concordÔncia é fraca entre as técnicas de PCR utilizadas para a detecþÒo de DNA de T. cruzi (k=0,37, 49% positivas por qPCR vs. 11% para a PCR convencional, p=0,0001). Nas amostras de sangue, os valores diagnósticos de qPCR em relaþÒo a PCR convencional foram de 100% sensibilidade; 78% de especificidade; 30% de VPP; 100% VPN; 4,6 RVP; 0 RVN. Para as amostras de músculo esquelético, os seguintes valores diagnósticos de qPCR foram obtidos: 100% sensibilidade; 29% de especificidade; 20% de VPP; 100% VPN; 1,4 RVP; 0 RVN. Ambas as técnicas sÒo igualmente sensíveis na faixa de concentraþÒo média-alta, mas qPCR foi mais eficaz na detecþÒo de baixas cargas parasitárias, especialmente em amostras de tecido.(AU)