Prevalence and seasonal variation of Fasciola hepatica in slaughtered cattle: the role of climate and environmental factors in Mexico.

The objective of this study is to determine the prevalence of Fasciola hepatica infection in cattle slaughterhouses, as well as its association with climatic/environmental factors (derived from satellite data), seasonality and climate regions in two states in Mexico. Condemned livers from slaughtered animals were obtained from three abattoirs in the states of Puebla and Veracruz. The overall prevalence of the parasite in cattle between January and December of 2017 was 20.6% (1407 out of 6834); the highest rate of condemnation was observed in Veracruz (26.3%; tropical climate), and the lowest rate was found in Puebla (15.5%; temperate climate). The seasonal prevalence of fluke infection was 18.6%, 14.8% and 28.4% during the wet season, and 17.1%, 12.4% and 22.8% during the dry season in the three abattoir sites, located in the districts of Zacatlán, Teziutlán and Ciudad Alemán, respectively. Liver condemnations due to bovine fasciolosis were prevalent in the Zacatlán, Teziutlán and Ciudad Alemán districts during summer, autumn and summer, respectively. Using generalized estimating equations analysis, we determined six variables - rainfall (wet/dry), land surface temperature day, land surface temperature night, normalized difference vegetation index, seasonality and climate regions (temperate/tropical) - to be significantly associated with the prevalence of condemned livers. Climate region was the variable most strongly associated with F. hepatica infection (odds ratio (OR) 266.59; 95% confidence interval (CI): 241.90-353.34), followed by wet and dry seasons (OR 25.56; 95% CI: 20.56-55.67).

Motility of Fasciola hepatica miracidia assessed with a computer-assisted sperm analyser.

The motility parameters of Fasciola hepatica miracidia were assessed at different temperatures and times post-hatching using computer-assisted sperm analysis. Eggs were incubated at 22 °C or 25 °C for 14 days. Five motion parameters were evaluated at different incubation temperatures up to 10 h post-hatching. No differences were observed in the percentage that hatched after incubation at the two different temperatures. However, the straight-line velocity of miracidia following incubation at 22 °C was significantly different from that observed at 25 °C (P< 0.01). All miracidium motion parameters at different post-hatching temperatures showed an overall decrease at the end of the experiment. Those miracidia hatching from eggs incubated at 25 °C had a higher velocity of 1673.3 µm/s compared with 1553.3 µm/s at 22 °C. Velocity parameters increased as the post-hatching temperature increased from 22 °C to 37 °C.

In Vitro Anthelmintic Activity of Methanolic Extract from Caesalpinia coriaria J. Willd Fruits against Haemonchus contortus Eggs and Infective Larvae.

The aim of this study was to evaluate the in vitro lethal effect of a methanolic extract (ME) from Caesalpinia coriaria fruits against Haemonchus contortus eggs and infective larvae. The anthelmintic activity was assessed using the egg hatching inhibition assay (EHI) and the mortality test. The ME was assessed using five concentrations as follows: 6.15, 3.12, 1.56, and 0.78 mg/mL to eggs and 150, 100, 75, and 50 mg/mL to larvae, respectively. Ivermectin (5 mg/mL) was used as positive control and 4% methanol and distilled water were used as negative controls. The data of ovicidal and larvicidal effect were analyzed with a completely randomized design through ANOVA analysis using the general linear model (GLM) and lethal concentrations (LC50 and LC90) were estimated through a Probit analysis using the SAS program. A clear ME increased concentration dependence effect was observed in the EHI and mortality tests. The highest activity of the methanolic extract was observed at the highest concentration (P < 0.05) to obtain a similar effect to the positive control (ivermectin), with LC50 = 78.38 and 0.00064 mg/mL and LC90 =235.63 and 0.024 mg/mL, respectively, for larvae and eggs. The results indicate that the C. coriaria fruit ME possesses in vitro ovicidal and larvicidal properties (gallotannins: methyl gallate) against H. contortus that needs to be investigated more in vivo for the control of gastroenteric nematodes in ruminants.