Toxoplasmosis in Mexico: epidemiological situation in humans and animals.

Toxoplasmosis is a parasitic disease widely distributed throughout the world, infecting a wide variety of animal species including humans. In Mexico, this parasite has been detected in different parts of the country, particularly in the tropical areas where the parasite can remain infective for long periods of time due to the environmental conditions (i.e. high temperature and humidity over the whole year). Several epidemiological studies have been conducted in both human and animal populations, but despite the wide distribution of the agent in the country, there is a significant lack of knowledge on the parasite transmission, treatment alternatives and control measures. The lack of feral cat populations and control measures in sites of meat production for human consumption are playing a role that has led to the wide spread of the disease in the country, particularly in tropical areas of Southeastern Mexico. For these reasons, this manuscript aims to review the published information on relevant epidemiological aspects of infection with T. gondii in humans and animals from Mexico.

Toxoplasmosis i Mexico: epidemiological situation in humans and animals / Toxoplasmosis en México: situación epidemiológica en humanos y animales

Toxoplasmosis is a parasitic disease widely distributed throughout the world, infecting a wide variety of animal species including humans. In Mexico, this parasite has been detected in different parts of the country, particularly in the tropical areas where the parasite can remain infective for long periods of time due to the environmental conditions (i.e. high temperature and humidity over the whole year). Several epidemiological studies have been conducted in both human and animal populations, but despite the wide distribution of the agent in the country, there is a significant lack of knowledge on the parasite transmission, treatment alternatives and control measures. The lack of feral cat populations and control measures in sites of meat production for human consumption are playing a role that has led to the wide spread of the disease in the country, particularly in tropical areas of Southeastern Mexico. For these reasons, this manuscript aims to review the published information on relevant epidemiological aspects of infection with T. gondii in humans and animals from Mexico.

La toxoplasmosis es una enfermedad parasitaria ampliamente distribuida en todo el mundo y puede infectar a una gran diversidad de especies animales y a los humanos. En México, esta parasitosis ha sido detectada en diferentes partes del país, en particular en las zonas tropicales en donde debido a las condiciones ambientales (ej. alta temperatura y humedad a lo largo todo el año), el parásito puede mantenerse infectante por largos períodos de tiempo en el medio ambiente. Se han realizado diversos estudios epidemiológicos tanto en poblaciones humanas como en animales y se observa que a pesar de la amplia distribución y buen establecimiento del agente en el país, existe un importante desconocimiento desde la epidemiologia, tratamientos alternativos o las medidas de control. La falta de control de las poblaciones ferales de felinos así como el establecimiento de medidas de control en unidades de producción de carne de diferentes especies para consumo humano están jugando un papel primordial que ha favorecido la amplia diseminación de la enfermedad en el país, principalmente en las zonas tropicales del sureste mexicano. Por lo que este manuscrito tiene como objetivo revisar la información publicada hasta ahora que nos describe aspectos epidemiológicos relevantes de la infección por T. gondii en humanos y animales de México.

Prevalence and Risk Factors of Toxoplasma gondii Infection in Domestic Cats from the Tropics of Mexico Using Serological and Molecular Tests.

The aim of this study was to determine the prevalence and risk factors associated with Toxoplasma gondii infection in domestic cats using an indirect-ELISA (IgM and IgG) and PCR. Samples collected from 220 cats from Merida, Yucatan, Mexico, were analyzed. Cases were reported as acute or chronic. Cases when positive to IgM and IgG and PCR were considered as reactivated chronic infection. Risk factors (sex, age, body condition, diet access to hunting, and number of cats in home) were assessed with a multivariate analysis, 75.5% (166/220) of the cats were IgM and 91.8% (202/220) IgG-seropositive and 79% were PCR-positive (173/220). Number of cats per household and low body condition score were associated with reactivated chronic infection (P < 0.05). It is concluded that T. gondii is scattered in the studied population with several periods of reinfection, and therefore an environmental contamination with infecting oocysts exists and there are intrinsic associated factors in cats that increase the risk of becoming infected.

In vivo activity of (8-hydroxymethylen)-trieicosanyl acetate against Trypanosoma cruzi during acute phase of the infection.

The antiprotozoal activity in vivo against Trypanosoma cruzi of (8-hydroxymethylen)-trieicosanyl acetate was evaluated in BALB/c mice during the acute phase of Chagas' disease (15 days after infection). Animals were treated during 15 days at doses of 16.8 and 33.6 µg/g, reduced parasitemia of 77.6 and 64.1% was observed respectively, in comparison with positive control mice (allopurinol 8.5 µg/g) which reduced only 29.7%. Also, amastigote nests in cardiac tissue were significant reduced in treated mice groups. The regression of effect induced after the suppression of the treatment with the compound was evaluated; animals were infected and simultaneously began the treatment with the compound during 20 days (16.8 and 33.6 µg/g). Mice were monitored after the end of the treatment for one more week. A good antitrypanosomal response was observed (66.1 and 68.9% less than untreated mice) during treatment, but 8 days after suspension of treatment, parasitemia level increased, reducing only 58.6 and 56.29 % respectively in treated animals compared with no treated.

Importancia de la caracterización de cepas de Trypanosoma cruzi / The importance of the characterisation of Trypanosoma cruzi strains

El trypanosoma cruzi (T. cruzi) es un protozoario hemoflagelado, considerado el agente causal de la enfermedad de Chagas y es transmitido a los hospederos mamíferos por medio de insectos vectores del género Triatoma. El T. cruzi presenta un pleomorfismo natural, al cual se ha atribuido a la diferencia de severidad con que se presenta la enfermedad en el hospedero humano y otros mamíferos. Considerando este aspecto han sido varios los trabajos sobre caracterización de cepas de T. cruzi, abarcando aspectos biológicos, bioquímicos y moleculares para poder establecer un método de clasificación de las diferentes cepas de dicho parásito, de manera que las cepas que pertenezcan a un mismo grupo compartan estos aspectos y así una cepa pudiera ser representativa de ese grupo, simplificando los estudios a realizar. Esta revisión pretende dar un panorama de los diferentes métodos de caracterización de la cepas T. cruzi, para tratar de agruparlas para su mejor estudio y control