Seasonal transmission of Fasciola hepatica in cattle and Lymnaea (Fossaria) humilis snails in central Mexico

Abstract

A 19-month study on the prevalence of fasciolosis in 30 naturally infected cows, the presence of infected and non-infected Lymnaea (Fossaria) humilis snails, and variation in soil temperature and humidity is reported. The prevalence of fasciolosis in cattle declined from around 50% in March to 30% in July, then, it increased from August, reaching a plateau of 100% in November-January, before gradually declining thereafter. A rise in soil humidity and temperature in June and July, respectively, which peaked between August and November was observed. In July, L. (F.) humilis snails appeared, but the infection could only be found in these in August and November. The number of infected snails did not reflect the infestation rate in cows, even though the infestation kinetics in both hosts behaved as predicted from the life cycle of the parasite.

Mineralization of atrazine in agricultural soil: Inhibition by nitrogen

“…The containers were incubated at 35 ± 1°C (mean ± standard error throughout) and opened daily for 1 min, assuring appropriate provision of oxygen to the system. This experimental temperature was selected because previous studies indicated that surface temperatures in tropical soils are greater than 30°C during several months of the year [21]. At certain time intervals, 1‐ml aliquots of the NaOH solution were sampled and transferred to Wheaton “180” borosilicate glass scintillation vials (Wheaton Science Products, Millville, NJ, USA) and mixed thoroughly with 8 ml of liquid scintillation cocktail (EcoLume, Costa Mesa, CA, USA).…”

Transmission dynamics of Fasciola hepatica in the Plateau Region of Mexico. Effect of weather and treatment of mammals under current farm management

“…Several studies have indicated a relation between humidity and/or temperature with the emergence of lymneid snails and their infestation by F. hepatica, albeit the period of the year when they peak depends on the species of the mollusc and the location of the study area, especially its altitude (Malone et al, 1985;Manga-Gonzáles et al, 1991;Rangel, 1999;Cañete et al, 2004;Kleiman et al, 2004Kleiman et al, , 2007Cruz-Mendoza et al, 2004, 2005. In places like Ireland, where the temperature is around 29 • C the whole year, the snails are rarely in aestivation and the prevalence in livestock has small fluctuations (Ross, 1977).…”

“…After the pioneering work by Mazzotti et al (1956) based on inspection of ruminant livers in slaughterhouses, numerous publications have demonstrated a high prevalence of F. hepatica in livestock in Mexico (Encinas et al, 1989;Castellanos et al, 1992;Robles, 1993;QuirozRomero, 1997;Cruz et al, 1999;Rangel et al, 1999;Cruz-Mendoza et al, 2005;Munguía-Xochihua et al, 2007). There is also information available indicating that the snails Lymnaea bulimoides, Lymnaea columella, Lymnaea cubensis, Lymnaea humilis, Lymnaea obrussa, Lymnaea truncatula and Lymnaea viatrix are frequent intermediate host species in the country (Castro-Trejo, 1997;Rangel, 1999;Cruz-Mendoza et al, 2002, 2005.…”

“…In a third study, the transmission dynamics was studied along one year in a hyperendemic region of Hidalgo, Central Mexico. A rise in humidity was followed by an increase in the number of infected and non-infected L. humilis, and some weeks later, of fasciolosis in cattle (Cruz-Mendoza et al, 2005).…”

Serological and coprological analyses for the diagnosis of Fasciolagigantica infections in bovine hosts from Sargodha, Pakistan

“…In the present study, elevated prevalence of fasciolosis was observed after peak rainfall in the month of August as relative humidity had increased. Cruz-Mendoza et al (2005) observed an increase in population of infected and non-infected snails after a rise in humidity, and some weeks later an elevated prevalence of fasciolosis in cattle.…”