RESUMO

Paratuberculosis (PTB) is a disease that affects cattle (Bos taurus), goats (Capra aegagrus hircus), sheep (Ovis aries), and wild animals, such as white-tailed deer (Odocoileus virginianus), since all ruminants are susceptible. The causal agent is Mycobacterium avium subsp. paratuberculosis (MAP). The disease is chronic, consumptive, and incurable; it causes chronic granulomatous gastroenteritis with lymphangiectasis and lymphangitis leading to a syndrome of malnutrition and eventually to death. Mycobacterium avium subsp. paratuberculosis is transmitted in feces mainly orally; however, it can also be transmitted vertically. Thus, the objective of this study was to determine the seroprevalence of MAP antibodies and its relationship to age and sex of Texas white-tailed deer in the subclinical stage of PTB in Coahuila, Mexico. The entire population (n=99) belonging to the Wildlife Management and Conservation Unit (WMCU) San Juan, Monclova, Coahuila, Mexico was captured. Mycobacterium avium subsp. paratuberculosis was diagnosed using an enzyme-linked immunosorbent assay by serologic test. Seroprevalence variables of adult vs. young females and males vs. females were compared. The treatments were assigned at random. For the analysis of data, the chi-square test was used. Total seroprevalence in an intensive WMCU was 16% (16/99). Total seroprevalence by sex was 5.0% (5/99) for males and 11% (11/99) for females, and total seroprevalence by age was 7% (7/99) for young and 9% (9/99) for adult. Within sex, the seroprevalence in males was 16% (5/31) and 16% (11/68) in females. There were no statistical differences for any of the comparisons. Total seroprevalence of the white-tailed deer population in the WMCU was 16%, and PTB seroprevalence was independent of sex or age of the sampled individuals of this population.

Assuntos

RESUMO

The Media Luna lake-spring was selected as representative of all thermal or no thermal springs in the zone of Valley of Rioverde, a semi-arid vegetation in the North-eastern of Mexico. This system is inhabited by 11 fish species, of which six are native. Four of the native species are endemic to the region and threatened due to touristic pressure and to the introduction of exotic species. The objectives were to determine the characteristics that influence the spatial distribution of the fish species, to analyze their spatial distribution patterns, and to describe the relationships between the different species. The general aim was to establish some basis for the conservation of these fish communities and their habitat. Several sessions were initiated in 1992 through direct observation. Later, between 1998 and 1999 five systematically seasonal sampling sessions were conducted (54 subaquatic transects/session). Finally, the data was updated by sampling in summer 2002 and winter 2006. Through the analysis was performed only for endemics of the region, like Ataeniobius toweri Meek, Cualac tessellatus Miller, Cichlasoma bartoni Bean and C. labridens Pellegrin, in at least one life stage, showed correlation with habitat variables or with other species. For these species, patterns of spatial aggregation and association with other species were observed. These results show a certain degree of specialization of endemic species to some microhabitat characteristics, as well as a significant interaction with other native species which they coexist. In addition, some significant relations between endemic and alien species suggest an antagonist relation. Management actions focused in the touristic use of the spring represent the main threat for these species, followed by an adequate management of exotic species. This study provides basis for future responsible management of these wetlands, where tourism and conservation can be combined.

Assuntos

RESUMO

The Media Luna lake-spring was selected as representative of all thermal or no thermal springs in the zone of Valley of Rioverde, a semi-arid vegetation in the North-eastern of Mexico. This system is inhabited by 11 fish species, of which six are native. Four of the native species are endemic to the region and threatened due to touristic pressure and to the introduction of exotic species. The objectives were to determine the characteristics that influence the spatial distribution of the fish species, to analyze their spatial distribution patterns, and to describe the relationships between the different species. The general aim was to establish some basis for the conservation of these fish communities and their habitat. Several sessions were initiated in 1992 through direct observation. Later, between 1998 and 1999 five systematically seasonal sampling sessions were conducted (54 subaquatic transects/session). Finally, the data was updated by sampling in summer 2002 and winter 2006. Through the analysis was performed only for endemics of the region, like Ataeniobius toweri Meek, Cualac tessellatus Miller, Cichlasoma bartoni Bean and C. labridens Pellegrin, in at least one life stage, showed correlation with habitat variables or with other species. For these species, patterns of spatial aggregation and association with other species were observed. These results show a certain degree of specialization of endemic species to some microhabitat characteristics, as well as a significant interaction with other native species which they coexist. In addition, some significant relations between endemic and alien species suggest an antagonist relation. Management actions focused in the touristic use of the spring represent the main threat for these species, followed by an adequate management of exotic species. This study provides basis for future responsible management of these wetlands, where tourism and conservation can be combined. Rev. Biol. Trop. 58 (1): 413- 426. Epub 2010 March 01.

Este estudio se enfocó en los peces de un sistema dulceacuícola en el noreste de México, donde habitan seis especies nativas (cuatro endémicas amenazadas) y cinco exóticas. El objetivo fue establecer los patrones que determinan la distribución espacial, así como las interrelaciones de las especies. Los datos se basan en sesiones de observación directa desde 1992; entre 1998 y 1999 se llevó a cabo un muestreo sistematizado mediante transectos subacuáticos en cinco sesiones estacionales (54 transectos/ sesión), con sesiones adicionales en 2002 y 2006. Sólo las especies endémicas de la región: Ataeniobius toweri, Cualac tessellatus, Cichlasoma bartoni y C. labridens, en al menos un estadio de vida, mostraron correlación significativa con variables del hábitat o con otras especies. También mostraron patrones de agregación y asociación con otras especies nativas o introducidas. Existe especialización de los endémicos a las condiciones de su microhábitat, así como interacciones significativas con otras especies. Acciones inadecuadas para promover el turismo representaron la mayor amenaza por destrucción del hábitat, endémicos tales como A, toweri y C. bartoni enfrentan solapamiento con especies introducidas, sobre todo en sus sitios de crianza. Este estudio aporta bases para un manejo responsable de estos humedales, donde turismo y conservación pueden combinarse.

Assuntos