Twice upon a time: The progression of canine visceral leishmaniasis in an Argentinean city.

Canine Visceral Leishmaniasis (CVL) prevalence, spatial distribution and associated factors were assessed in four locations in Iguazú department in 2014 and in Puerto Iguazú city again in 2018. The city areas were divided into a grid of 400x400m cells. All cells were sampled in 2014 and a random subsampling was developed in 2018. In each cell, five dogs clustered in a 'critical scenario' (prone to have vectors) were sampled. A rapid immunochromatographic dipstick was used to detect antibodies against Leishmania infantum, confirming by lymph node smears observation and PCR. For Puerto Iguazú, Generalized Linear Models (GLMs) were constructed considering environmental, dog and clinical variables. Pearson's Chi square and Fisher's exact tests were employed to evaluate the association between CVL, dog clinical signs and infestation with other parasites. Cartographic outputs were made and Moran's I indices were calculated as spatial autocorrelation indicators. CVL prevalence rates were 26.18% in 2014 and 17.50% in 2018. No associations were established in environmental models, but dog age and repellent use were significant when running 2014 dog models. Clinical models showed significant associations between seropositive dogs and ophthalmological, dermal signs and onychogryphosis in 2014. In 2018, only adenomegaly was associated. The results of global Moran´s I were not significant but regarding local analysis, six sites in 2014 and one in 2018 presented autocorrelation with neighboring sites. The decrease in CVL prevalence may be associated to transmission stabilization, which could explain the lack of associations with dog-related variables. Further, spatial distribution of CVL is a poor evidence for design of transmission control measures but could be important in case of intensive parasite circulation or when the first autochthonous cases appear. For control success, sensitivity of diagnostic methods, political will and adequate material resources remain critical. Modeling of multiple variables will be required to identify factors that drive disease stabilization/destabilization.

Factors associated with hard tick (Acari: Ixodidae) parasitism in medium-sized mammals in the Atlantic Rainforest region of Argentina.

Associations with environmental and host parameters were assessed to describe tick parasitism patterns in two medium-sized mammals of the Atlantic rainforest region of Argentina. Ticks found on 93 specimens of Nasua nasua and 26 specimens of Didelphis aurita captured at six sites in the Iguazú National Park were collected. Generalized linear models were constructed to explain the presence and abundance of ticks and the most appropriate ones were selected after stepwise simplification. The season, site and host body mass variables were important to explain the abundance of Amblyomma coelebs nymphs, while site was important to describe larval abundance of this species. Season was the most important variable for larvae and nymphs of Haemaphysalis juxtakochi, while Amblyomma brasiliense nymphs were associated with host age. Amblyomma ovale larvae were related to host age, and adult ticks with host sex. The results indicate that these medium-sized mammals are important to support the immature tick stages and that both host and environmental factors may be associated with parasite loads.

Filarias zoonóticas en carnívoros domésticos y silvestres del norte de la provincia de Misiones, Argentina / Zoonotic filariae in domestic and wild carnivores from the north of Misiones province, Argentina

Las filarias son nematodes que se transmiten por artrópodos hematófagos y afectan a carnívoros domésticos y silvestres. Se han descripto como enfermedades zoonóticas, especies de filarias que parasitan naturalmente a los mamíferos y la más frecuente en América es Dirofilaria immitis. La aparición de las zoonosis constituye un grave problema para la salud pública. Sin embargo, aspectos relacionados con la eco-epidemiología de estas enfermedades han sido poco estudiados. Este trabajo se realizó con el objetivo de establecer la riqueza y prevalencia de especies de filarias en carnívoros domésticos y silvestres en el noroeste de Misiones e identificar las especies de filarias que presentan un potencial riesgo zoonótico para la población. Con la Técnica de Knott se analizaron un total de 196 muestras de las cuales 34 correspondían a carnívoros silvestres y 160 a domésticos. Hallamos microfilarias en el 65.38% de coaties (17/26), mientras que para los carnívoros silvestres restantes (8) y los domésticos (160) el resultado fue negativo. En los coatíes se hallaron microfilarias de 197 µm de largo, con vaina mucho más larga que el cuerpo, cola aguzada con núcleo terminal. Estas características se corresponden con Brugia sp. Otras microfilarias caracterizadas como "tipo 1" de 237 µm, sin vaina y cola con extremo redondeado con núcleo y microfilarias caracterizadas como "tipo 2" de 278 µm, sin vaina y cola aguzada levemente curvada. Éstas dos últimas microfilarias halladas en los coatíes podrían corresponder a Mansonella sp. y a Acanthocheilonema reconditum. De los análisis moleculares, se pudieron obtener 11 secuencias legibles de las cuales ocho se correspondieron con Mansonella ozzardi en un 87-90% de la secuencia y tres arrojaron un 87% de similitud con Wuchereria bancrofti