Occurrence of sarcoptic mange in free-ranging vicuñas (Vicugna vicugna) of the Andean high plateau region of Argentina.

Free-ranging vicuñas (Vicugna vicugna) are handled in some areas of the Andean high plateau region following an ancestral practice known as chaku, which consists in their transient capture and shearing of their fiber for commercialization. In this study, 807 vicuñas captured during 12 chaku events that took place in 2019 in the province of Jujuy, Argentina, were examined for typical mange skin lesions. Twenty-eight of the examined vicuñas presented alopecia with erythema, exudation, hyperkeratosis, and/or bleeding scarred lesions, mostly in the chest, rear and front legs, and inguinal zone. Most of the cases (82%) appeared in Laguna Cucho at 4900 masl, where 23% of the animals presented these skin reactions. Microscopic evaluation of skin scrapings revealed the presence of a great number of 0.1- to 0.4-mm-long mites of different life cycle stages, morphologically compatible with the species Sarcoptes scabiei. This etiological agent was confirmed by PCR amplification and sequencing of a cox-1 species-specific segment. Histopathological examination of skin biopsies showed extensive infiltration of the dermis with lymphocytes, neutrophils and eosinophils, hyperplasia at different stages, epidermis degeneration, and hyperkeratosis. This is the first characterization of sarcoptic mange in free-ranging vicuñas by clinical examination, mite morphology, histopathological studies, and molecular confirmation in the region. Mange hampers the welfare of vicuñas and the economy of the local communities that organize chaku events since infested vicuñas cannot be sheared. Its long-term effects are unknown but it might affect the fitness and survival of this iconic South American camelid.

Gastrointestinal nematodes and mineral deficiencies in yearling cattle in Santiago del Estero, northern Argentina.

The aims were to study the epidemiology and the effect of gastrointestinal nematodes (GINs) on yearling cattle in a semiarid region in Argentina and to evaluate the mineral serum levels. Ten- to twelve-month-old calves were monitored between November and April 2019. Animals were divided into three groups: untreated control (CONG; n = 20); group treated with moxidectin (MXD, 200 µg/kg) every 30-40 days (MXDG; n = 20); group equally MXD treated and mineral supplementation administered in November and January (MMG; n = 20). Individual GIN egg counts (epg) and fecal cultures were made every 30-40 days. Animal live weight gain was determined. On 7-11-18, 25-1-19, and 3-4-19, serum levels of Se, Cu, Zn, Mg, and Ca were determined by atom absorption spectrophotometry. At the start of the trial, epg values were low (x̄ = 5.5), which increased only in CONG towards the end of the assay (x̄ = 229). In both GMXD and MMG, epg remained very low (x̄ = 4.1). Cooperia spp. (81%) prevailed over Haemonchus spp. (9%) and Oesophagostomum spp. (9%). Deficiency of Se ranged between marginal and important, except for MMG, although mean values were always below normal. Cu was marginally deficient in CONG and MXDG on the first two sampling dates, whereas MMG had normal values after treatment. Mg had low values in the three groups (x̄ = 1.5 mg/dl), whereas Ca and Zn exhibited normal values. Live weight gain (LWG) was higher in MMG than in MXDG, with significant differences (p < 0.05) by mid-January and then, when epg increased, dewormed groups showed higher LWG (p < 0.034) than CONG. A negative effect of GINs on LWG was observed, as well as low to marginal levels of Se, Cu, and Mg.

Natural infection in Pampas fox (Lycalopex gymnocercus) by Lagochilascaris major Leiper, 1910 (Nematoda: Ascarididae) in Buenos Aires, Argentina.

Lagochilascariosis is an emerging parasitic disease limited to the American continent, caused by nematodes of the genus Lagochilascaris. Its life cycle is heteroxenous, involving natural definitive hosts (wild carnivores), accidental hosts (domestic carnivores and humans), and intermediate hosts (rodents). Here we report, for the first time, the occurrence of Lagochilascaris major in female of a Pampas fox (Lycalopex gymnocercus) which was found in the Mar Chiquita basin, Buenos Aires province, Argentina. At necropsy, multiple Lagochilascaris larvae and several adults (1 female and 5 male) were observed inserted in the mucosa of the trachea and a male was also collected in the stomach. The diagnosis was made by observing the different stages with optical microscopy, by scanning electron microscopy of adult males and coproparasitological analysis. Although cases of lagochilascariosis have been reported in wildlife in different countries of the American continent, in Argentina, cases are really rare and were only found in domestic cats. Graphical abstract ᅟLagochilascariosis is an emerging parasitic disease limited to the American continent. In Argentina, sporadic cases of Lagochilascariosis were reported in domestic cats but this work represents the first record in a wild carnivore (L. gymnocercus) naturally infected with L. major.

The Efficacy of a Trivalent Inactivated Salmonella Vaccine Combined with the Live S. Gallinarum 9R Vaccine in Young Layers after Experimental Infections with S. Enteritidis, S. Typhimurium, and S. Infantis.

Worldwide, poultry infections by Salmonella are the cause of significant economic losses, not only due to reduced production (due to fowl typhoid disease), but also considering the efforts and control measures that must be constantly applied, especially due to zoonotic serovars. Poultry is a common reservoir of Salmonella and its transmission into the food chain is a risk for humans. The vaccination of layers plays an important role in the overall efforts to prevent Salmonella infections. An inactivated trivalent vaccine was prepared with S. Enteritidis, S. Typhimurium, and S. Infantis strains. Infection trials were performed to evaluate the efficacy of three vaccination schedules using inactivated and live S. Gallinarum 9R vaccines. For this purpose, at week 5 of life, one subcutaneous dose of live S. Gallinarum 9R vaccine (1-5 × 107 CFU) was given to Groups 1 and 2. At weeks 8 and 11 of life, chickens were also vaccinated with one (Group 1) or two (Groups 2 and 3) intramuscular doses of the inactivated oil-adjuvant trivalent vaccine (1 × 108 CFU/dose of each antigen). Group 4 consisted of chickens that remained unvaccinated (control). At week 14 of life, the efficacy of the vaccination plans was evaluated in three separate inoculation trials with S. Enteritidis, S. Typhimurium, or S. Infantis. After vaccination with the inactivated vaccine, homologous antibody production was observed, and after challenge, a significant reduction in the faecal shedding, invasion, and colonization of S. Typhimurium and S. Infantis was achieved by all vaccination schedules, while the vaccination with at least one dose of the live S. Gallinarum 9R vaccine was necessary to obtain such a significant protection against S. Enteritidis infection.

Pampas fox (Lycalopex gymnocercus) of the Argentine Pampas as intermediate host for Neospora caninum.

The Pampas fox (Lycalopex gymnocercus) is the most abundant wild canid from South America. This wild canid inhabits grasslands, open woodlands, and areas highly modified by extensive ranching and agricultural activities. We aimed to evaluate Neospora caninum infection in tissues from the Pampas fox from Argentina. A total of 41 free-living Pampas foxes were sampled in rural areas located in the Humid Pampas region, Argentina. Brain tissue and different muscles were assessed by histologic and molecular methods. No N. caninum cysts were observed in brain and muscle tissue samples analyzed by histology and immunohistochemistry. Molecular N. caninum identification from brain tissue was based on amplification by PCR of Nc-5 gene and ITS1 rRNA fragments and subsequent sequencing. The presence of N. caninum DNA was 74% (23/31) for the Nc-5 gene and was confirmed by a second ITS1 PCR in 55% (17/31) of the brain tested. Thirteen ITS1 consensus sequences were obtained, and all have a 99.58-100% similarity with N. caninum reference sequences. Only 4% (1/23) of muscles samples analyzed were positive for the Nc-5 gene of N. caninum. This study demonstrated a high prevalence of N. caninum DNA in brain from free-ranging Pampas fox of the Pampa Argentine, thus confirming that this wild canid is a wide distributed intermediate host.

Dinámica de contaminación de pasturas con huevos de nematodos gastrointestinales de bovinos en el Valle de Lerma, Salta / Dynamics of pasture contamination with bovine gastrointestinal nematode eggs in the Lerma Valley, Argentina

Resumen El Valle de Lerma (VDL) es una región ubicada en la parte central de la provincia de Salta, República Argentina, la cual da origen a la mayor parte de la producción láctea provincial. La nematodiasis gastrointestinal es uno de los problemas sanitarios de mayor impacto económico en los sistemas productivos de base pastoril. El objetivo de este trabajo fue caracterizar la variación estacional de la eliminación de huevos y géneros de nematodos al medio ambiente. Mensualmente se tomaron muestras de materia fecal en bovinos de recría para conteo de huevos por gramo (HPG) y coprocultivo para determinación de géneros en tres establecimientos ganaderos de la región. En todos ellos se observaron dos picos en los valores medios de HPG, que ocurrieron entre principios de verano y fines de otoño. Los géneros/especies más prevalentes fueron Cooperia pectinata, Haemonchus spp. y Cooperia punctata, seguidos por Oesophagostomum spp., Trichostrongylus spp. y Ostertagia spp. Estos resultados aportan nueva evidencia al conocimiento de la epidemiología de los nematodos gastrointestinales de los bovinos en la región del VDL.

Abstract The Lerma Valley (LV) is a region located in the central part of the province of Salta, Argentine Republic. The largest dairy production in the province originates in this region. Gastrointestinal nematodiasis is one of the health problems with the greatest economic impact in pastoral-based production systems. The objective of the present work was to characterize the seasonal variation of the elimination of eggs and genera of nematodes to the environment. Fecal matter samples were taken from rearing cattle to count eggs per gram (Epg) and culture for gender determination monthly in three farms in the region. In these, it was possible to observe that the Epg values ​​showed two peaks, which occurred between the beginning of summer and the end of autumn. Regarding the genera/species, the most prevalent were Cooperia pectinata, Haemonchus sp. and Cooperia punctata, followed by Oesophagostomum spp., Trichostrongylus spp. and Ostertagia spp. These results contribute with new evidence to the knowledge of the epidemiology of gastrointestinal nematodes of cattle in the LV region.

Pampas fox (Lycalopex gymnocercus) new intermediate host of Sarcocystis svanai (Apicomplexa: Sarcocystidae).

Several Sarcocystis spp. have carnivores as definitive host and sarcocysts are common in muscles of herbivores (intermediate host). However, sarcocysts have been found in muscles of wild and domestic carnivores suggesting they are intermediate host for some Sarcocystis spp. Here, we report mature sarcocysts in the muscles of Pampas fox (Lycalopex gymnocercus). A total of 36 free-living foxes were analyzed. Different skeletal muscles were assessed by microscopic and molecular methods. Cysts and/or DNA of Sarcocystis sp. were detected in 61.1% (22/36) foxes. Histopathology revealed the presence of sarcocysts in 52.8% (19/36) foxes. The tongue and masseter were the muscles more frequently infected. Of all the samples processed by homogenization of pooled muscles of each animal, 45.4% (10/22) evidenced muscle cysts and 68.2% (15/22) resulted positives by PCR. Individual cysts obtained from the ten positive samples in direct microscopic examination were all positive by PCR. Five amplicons from individual cysts from different samples were selected for sequencing together with four PCR products obtained from the pooled muscles. All nine sequences shared a high identity among them (99.8-100%) and showed the highest identity by BLAST (99%) with a S. svanai sequence (KM362428) from a North American dog. By transmission electron microscopy, the sarcocyst wall was thin (<1µm), had minute undulations, with tiny evaginations and without evident villar protrusions. The cyst wall type is referred as "type 1". Sarcocystis svanai infects L. gymnocercus with a high prevalence and the presence of mature sarcocysts suggests the role of the Pampas fox as natural intermediate host. The definitive host of S. svanai remains unknown.