What do we know about parasites of wildlife in high biodiversity areas with anthropogenic disturbance? The special case of Mexico.

The continual rise of anthropogenic disturbance of ecosystems has been associated with an increasing incidence of emerging diseases. The largest amount of data on emerging diseases relates to bacterial and viral pathogens, but there is a lack of parasite data, especially from wildlife. Monitoring wildlife parasitic diseases should be considered a priority, especially in high biodiversity regions with strong anthropogenic impacts, like Mexico, where the wildlife/livestock/human interface is associated with increased risk of disease transmission. Mexico belongs to the top-ten megadiverse countries and is located between two biogeographic regions. This situation makes Mexico a favourable region for the spillover of animal pathogens to human beings, causing pandemics, such as the one recently caused by influenza virus A (H1N1). The current state of knowledge of Mexican wildlife parasites is scarce and focuses mainly in Neotropical fauna. Moreover, this knowledge is heterogeneous for different parasite groups, especially concerning their pathologic effects and epidemiology. The goals of this review are to compile information on Mexican wildlife parasites and to identify knowledge gaps in order to stimulate research on pending epidemiological, public health, ecological and pathological areas, and to encourage the creation of more specialized groups from the perspective of the One-Health concept.

Canine myiasis by Lucilia eximia in North America.

Myiasis is the invasion of Diptera larvae in live vertebrates tissues. It has been registered in tropical areas, but not in urban animals of North America. Moreover, there is no information about lesions description, laboratory tests, and treatment applied to canines. We report a myiasis located in the dorsum of an overweight male canine. Insect larvae were identified as Lucilia eximia, an opportunistic species that scarcely infest live vertebrates, and with no records in North America animals before. Abnormalities of complete blood count like leukocytosis by neutrophilia and serum biochemical changes like elevations in alanine aminotransferase, aspartate aminotransferase, creatine kinase, globulins and amylase were detected. Because Lucilia is characterized by lower host-specificity and infestation outbreaks occur worldwide, it is imperative to continue increasing the understanding of Lucilia myiasis, its clinical presentation, risk factors, therapy and correct entomological classification. Otherwise, more cases could occur in animals and humans.

Canine myiasis by Lucilia eximia in North America

Myiasis is the invasion of Diptera larvae in live vertebrates tissues. It has been registered in tropical areas, but not in urban animals of North America. Moreover, there is no information about lesions description, laboratory tests, and treatment applied to canines. We report a myiasis located in the dorsum of an overweight male canine. Insect larvae were identified as Lucilia eximia, an opportunistic species that scarcely infest live vertebrates, and with no records in North America animals before. Abnormalities of complete blood count like leukocytosis by neutrophilia and serum biochemical changes like elevations in alanine aminotransferase, aspartate aminotransferase, creatine kinase, globulins and amylase were detected. Because Lucilia is characterized by lower host-specificity and infestation outbreaks occur worldwide, it is imperative to continue increasing the understanding of Lucilia myiasis, its clinical presentation, risk factors, therapy and correct entomological classification. Otherwise, more cases could occur in animals and humans.

Evidence for widespread Leishmania infantum infection among wild carnivores in L. infantum periendemic northern Spain.

Leishmania spp. infection was investigated in tissue samples of wild carnivores from the Spanish Basque Country (BC), by PCR and DNA sequencing. The region is at the northern periphery of Leishmania infantum endemic Iberian Peninsula and infection in the dog (reservoir) or other species has not been previously reported. Leishmania kinetoplast DNA was detected by real-time PCR (rtPCR) in 28% (44/156) of animals. Specifically, in 26% of Eurasian badgers (n=53), 29% of foxes (n=48), 29% of stone martens (n=21) and in 25-50% of less numerous species including genets, wild cats, pole cats, European mink and weasels. Infected animals particularly badgers, were most prevalent in the southernmost province of the BC (Araba) in areas dominated by arable land. Subsequent amplification and sequencing of a fragment of the rRNA internal transcribed spacer 2 (ITS2) from a subset of rtPCR positives samples confirmed the species as L. infantum, showing a high sequence homogeneity with ITS2 sequences of L. infantum from dogs and humans from southern Spain. In summary, this study reports for the first time L. infantum infection in wild carnivores from the BC including in stone martens, pole cats and minks in which infection has not been previously described. It supports the need to study infection in dogs and people in this region and is an example of the value of infection surveillance in wildlife to assess potential risks in the domestic environment and their role in spreading infections in non-endemic areas.

Comparative value of microscopy, serology and real time pcr in the diagnosis of asymptomatic canine Leishmania infantum infection

Se investigó la sensibilidad (SE) del examen citológico mediante microscopia óptica (MO) de improntas de bazo y linfonodo, de la prueba de anticuerpos ELISA (inmuno-ensayo ligado a enzima) y de la PCR (reacción en cadena de la polimerasa) a tiempo real (tr), para diagnosticar la infección asintomática por Leishmania infantum en 110 perros aparentemente sanos, del sureste de España. El porcentaje de perros positivos a MO, ELISA y PCRtr fue 2% (2/110), 27% (26/97) y 67% (39/58), respectivamente, aunque el porcentaje de PCR-positivos osciló entre 35-41% para cada tejido individualmente y 9% en sangre. La SE estimada (intervalos de confianza del 95%) de la MO en relación a la PCRtr y al ELISA fue 5% (0-12) y 8% (0-18), respectivamente. Estos resultados confirman que la mayoría de perros aparentemente sanos de una población endémica de L. infantum están infectados, que aproximadamente solo la tercera parte de éstos desarrolla anticuerpos frente al parásito y solo unos pocos tienen suficiente carga parasitaria en tejido linfoide como para ser detectada mediante MO. Consecuentemente, el grado de concordancia de la PCRtr, el ELISA y la MO en el diagnóstico de leishmaniosis canina asintomática es escaso (AU)

The sensitivity (SE) of cytological examination of spleen and lymphnode smears by optical microscopy (OM), antibody-ELISA (enzyme-linked immunosorbent assays) and real-time (rt) PCR (polymerase chain reaction), for diagnosing asymptomatic canine Leishmania infantum infection was investigated in 110 apparently healthy dogs from southeast Spain. The percentage of OM, ELISA and rtPCR positive dogs were 2% (2/110), 27% (26/97) y 67% (39/58), respectively, although the percentage of rtPCR-positive dogs were 35-41% in individual tissues and 9% in blood. The estimated SE (95% confidence interval) of OM relative to the rtPCR and ELISA tests was 5% (0-12) and 8% (0-18), respectively. Results confirm that most apparently healthy dogs from L. infantum endemic areas are infected, that approximately only one third of these infected dogs develop antibodies and that very few have parasite loads that are high enough to allow detection by OM. As a result, the degree of agreement between rtPCR, ELISA and OM for L. infantum diagnosis in subclinnically infected dogs is low (AU)

Cryptic Leishmaniosis by Leishmania infantum, a feature of canines only? A study of natural infection in wild rabbits, humans and dogs in southeastern Spain.

An epidemiological study was carried out to investigate asymptomatic Leishmania infantum infection by PCR and ELISA in wild rabbits, humans and domestic dogs in southeastern Spain. Seroprevalence was 0% (0/36) in rabbits, 2% (13/657) in humans and 7% (14/208) in dogs. The prevalence of PCR-positives was 0.6% (1/162) in rabbits tested in a wide range of tissue samples, 2% (8/392) in humans analysed in blood samples and 10% (20/193) and 67% (29/43) in dogs analysed in blood and lymphoid tissue samples, respectively. Results suggest that wild rabbits have a very low risk of becoming chronically infected with L. infantum, and provide further evidence that cryptic L. infantum infection is widespread in the domestic dog population and is also present in a comparatively smaller proportion of healthy humans. The epidemiological and clinical implications of these findings are discussed.