Title : Prevalence of toxoplasmosis in populations of Tlacuaches (Didelphis albiventris), in the municipality of Morelia and its zoonotic relationship
Zoonotic diseases have always been of concern to humans, one of the most common is toxoplasmosis, a worldwide disease caused by the etiological agent Toxoplasma gondii (Carrada, 2005), which affects birds, mammals and man, Basso and Venturini (2009) mention that: “The infection has a variable clinical presentation according to the affected species and the individual immune status. In humans, it is frequently subclinical, but it can cause fetopathies if primoinfection occurs during pregnancy, as well as ocular lesions due to transplacental or postnatal infection, and encephalitis in immunosuppressed individuals. ”(Page 1).
Now, given the zoonotic importance and the little clinical signology that is presented, it requires greater sanitary controls, especially in vectors that can often be wild animals that we cannot imagine; Therefore, a species that has not been taken into consideration as a transmitter of this disease can be tlacuache (Didelphis albiventris), which is a marsupial that is distributed from southeastern Canada to Costa Rica and in Mexico, it can be located throughout the Republic except Baja California and the plateau north of Guanajuato (Portillo, L., 2008).
Eating habits make it an important vector in the transmission of toxoplasma gondii, since they are omnivorous that feed on fruits, seeds, plant sprouts, insects and other invertebrates, but also on vertebrates such as rats, mice, snakes, amphibians, fish and carrion, also eats eggs, chicks of wild and domestic birds (Portillo, L., 2008).
In the case of intermediate hosts, such as tlacuache, it is mainly infected with raw meat from other intermediate hosts containing viable forms of T. godii (tissue cysts, tachyzoites), by ingestion of water contaminated with oocysts. For this type of intermediate hosts the biological cycle is performed exclusively extraintestinal. Thus, the infectious forms penetrate different nucleated cells of the organism, multiplying as tachyzoites. In this period of rapid multiplication, in which the tachyzoites destroy the parasitized cells and spread within the host, being here where clinical manifestations occur. When the cells invade the host organism, they are mainly helped by a group of organelles that are located at the anterior end of the parasite called the Apical Complex that includes one or more electrodense polar dense rings, a cone, roptrias, micronema, dense granules and subpelicular microtubules. After this the parasites multiply more slowly, without destroying the host cell forming the tissue cysts, called bradyzoites, remaining viable for an indeterminate time, even during the whole life of the host (Basso, & Venturini, 2009).
Ferraro (2012) mentions that toxoplasmosis was cataloged as a parasitic disease transmitted by foods of an emergent nature, caused by ingestion of raw or undercooked meat as a contaminant, which comes from parasitized intermediate hosts. But it is important to consider that natural water and soil, with cat feces (definitive host), are also considered as potential sources of infection, so that they can establish endemic cycles (Ferraro, 2012, p. 14)
Based on the above, it is established the need to consider the population status of the population of Tlacuaches (Didelphis virginiana), in the municipality and the body condition, as well as the relationship it has as a vector in the transmission of toxoplasmosis in the population of the municipality of Morelia, with this the following objectives are established:
a) Characterize the relative density of the population of tlacuaches in the Municipality of Morelia.
b) Characterize the health status of the specimens.
c) Determine the prevalence of toxoplasmosis in populations of tlacuaches in the Municipality of Morelia, and
d) Determine the zoonotic degree of toxoplasmosis