Equines as reservoirs of human fascioliasis: transmission capacity, epidemiology and pathogenicity in Fasciola hepatica-infected mules.

Fascioliasis is a zoonotic disease caused by liver flukes transmitted by freshwater lymnaeid snails. Donkey and horse reservoir roles have been highlighted in human endemic areas. Liver fluke infection in mules has received very limited research. Their role in disease transmission, epidemiological importance and Fasciola hepatica pathogenicity are studied for the first time. Prevalence was 39.5% in 81 mules from Aconcagua, and 24.4% in 127 from Uspallata, in high-altitude areas of Mendoza province, Argentina. A mean amount of 101,242 eggs/mule/day is estimated. Lymnaeids from Uspallata proved to belong to ribosomal DNA internal transcribed spacer (ITS) markers ITS-1 and ITS-2 combined haplotype 3C of Galba truncatula. These lymnaeids were experimentally susceptible to infection by egg miracidia from mules. Infectivity, number of cercariae/snail and shedding period fit the enhanced F. hepatica/G. truncatula transmission pattern at very high altitude. This indicates that the mule is able to maintain the F. hepatica cycle independently. Individual burdens of 20 and 97 flukes were found. Mule infection susceptibility is intermediate between donkey and horse, although closer to the latter. Anatomo-pathology and histopathology indicate that massive infection may cause mule death. Haematological value decreases of red blood cells, haemoglobin, leucocytes and lymphocytes indicate anaemia and strong immunosuppression. Strongly increased biochemical marker values indicate liver function alterations. The mule probably played a role in the past exchanges with Chile and Bolivia through Mendoza province. Evidence suggests that mules could contribute to the spread of both F. hepatica and G. truncatula to human fascioliasis-endemic areas in these countries.

Especies de garrapatas (Acari: Ixodidae) parásitas de perros (Canis familiaris) en zonas urbanas del Gran Mendoza, Argentina

El conocimiento de las especies de ectoparásitos presentes en los animales de compañía tiene implicancias tanto en medicina veterinaria como en salud humana, ya que varios agentes tienen la potencialidad de transmitirse del animal al humano y viceversa. Se revisaron 466 garrapatas remitidas al Centro de Investigación en Parasitología Regional (CIPaR) durante los años 2010 y 2013, recolectadas en 217 perros de zonas urbanas de la provincia de Mendoza. El 83,5% (n=385) fueron identificadas como Rhipicephalus sanguineus sensu lato (84 machos y 199 hembras - relación 1:2,37 -, 65 ninfas y 37 larvas), mientras que el 16,5% (n=76) fue identificado como Amblyomma tigrinum (10 machos y 61 hembras - relación 1:6,1 -, y cinco ejemplares adultos en mal estado, imposibilitando su sexado). Adicionalmente, cinco ejemplares adultos sólo se identificaron como pertenecientes al género Amblyomma, ya que por encontrarse ingurgitados no se pudo realizar la determinación de especie. Éste registro es un importante aporte al conocimiento de las especies de garrapatas presentes en perros (Canis familiaris) en la provincia de Mendoza.

Knowledge of the ectoparasitic agents of pets has implications both in veterinary medicine and public health since several agents have the potential to spread from animal to human and vice versa. Ticks sent to the Centro de Investigación en Parasitología Regional (CIPaR) during 2010 to 2013 were analysed. 466 adult ticks were collected from 217 dog in urban areas from Mendoza province, Argentina. Of these, 83.5% (n=385) specimens were identified as Rhipicephalus sanguineus s.l. (84 male and 199 female - ratio 1:2.37 -, 65 nymphs and 37 larvae), while 16.5% (n = 76) were identified as Amblyomma tigrinum (10 males and 61 females - ratio 1:6.1 -, and five adults in bad condition, which precluded their sexing). In addition, five adult specimens, identified as Amblyomma, were not identified to the species level since they were fully engorged. This report is an important contribution to the knowledge of the species of ticks in dogs (Canis familiaris) in the province of Mendoza.

Characterisation of Lymnaea cubensis, L. viatrix and L. neotropica n. sp., the main vectors of Fasciola hepatica in Latin America, by analysis of their ribosomal and mitochondrial DNA.

Although, in the endemic areas throughout the world, human fascioliasis presents varying patterns in its epidemiology, the species of lymnaeid snail that act as intermediate hosts and vectors are always crucial in the transmission of the causative parasites. Species in the Galba/Fossaria group of snails, such as Lymnaea cubensis, L. viatrix var. A ventricosa, L. viatrix var. B elongata and Galba truncatula, appear to be frequently involved in the transmission of Fasciola hepatica in Central and South America, although specific classification within this morphologically and anatomically confusing group is often very difficult. To explore the potential use of molecular analyses in the identification of vector snails, regions of the ribosomal DNA - the small subunit (18S) gene and internal transcribed spacers (ITS-2 and ITS-1) - and of the mitochondrial DNA - the cytochrome c oxidase subunit I (COI) - of wild-caught lymnaeid snails of L. cubensis, L. viatrix var. A ventricosa, L. viatrix var. B elongata and G. truncatula have been sequenced. The samples of the Latin American species included specimens from the respective type localities. The genetic distances observed and the results of phylogenetic analyses demonstrate that two different species exist within L. viatrix. Lymnaea neotropica n. sp. (=L. viatrix var. B elongata) is here proposed for specimens from Lima, Peru, and is differentiated from L. viatrix (=L. viatrix var. A ventricosa), L. cubensis and G. truncatula. The data collected on the 18S ribosomal-RNA gene indicate that the snails investigated may cover more than one supraspecific taxon. The ITS-2, ITS-1 and COI nucleotide sequences are clearly useful markers for the differentiation of these morpho-anatomically similar lymnaeid species. The numerous microsatellite repeats found within ITS-2 are potential tools for differentiation at population level.