Epidemiology of sarcoptic mange in a geographically constrained insular red fox population.

BACKGROUND: Sarcoptic mange is a skin disease caused by the contagious ectoparasite Sarcoptes scabiei, capable of suppressing and extirpating wild canid populations. Starting in 2015, we observed a multi-year epizootic of sarcoptic mange affecting a red fox (Vulpes vulpes) population on Fire Island, NY, USA. We explored the ecological factors that contributed to the spread of sarcoptic mange and characterized the epizootic in a landscape where red foxes are geographically constrained. METHODS: We tested for the presence of S. scabiei DNA in skin samples collected from deceased red foxes with lesions visibly consistent with sarcoptic mange disease. We deployed 96-100 remote trail camera stations each year to capture red fox occurrences and used generalized linear mixed-effects models to assess the affects of red fox ecology, human and other wildlife activity, and island geography on the frequency of detecting diseased red foxes. We rated the extent of visual lesions in diseased individuals and mapped the severity and variability of the sarcoptic mange disease. RESULTS: Skin samples that we analyzed demonstrated 99.8% similarity to S. scabiei sequences in GenBank. Our top-ranked model (weight = 0.94) showed that diseased red foxes were detected more frequently close to roadways, close to territories of other diseased red foxes, away from human shelters, and in areas with more mammal activity. There was no evidence that detection rates in humans and their dogs or distance to the nearest red fox den explained the detection rates of diseased red foxes. Although detected infrequently, we observed the most severe signs of sarcoptic mange at the periphery of residential villages. The spread of visual signs of the disease was approximately 7.3 ha/week in 2015 and 12.1 ha/week in 2017. CONCLUSIONS: We quantified two separate outbreaks of sarcoptic mange disease that occurred > 40 km apart and were separated by a year. Sarcoptic mange revealed an unfettered spread across the red fox population. The transmission of S. scabiei mites in this system was likely driven by red fox behaviors and contact between individuals, in line with previous studies. Sarcoptic mange is likely an important contributor to red fox population dynamics within barrier island systems.

Multiple anthelmintic drug resistant Ancylostoma caninum in foxhounds.

Ancylostoma caninum is the most common and important gastrointestinal nematode of dogs in the United States. Despite recent reports of A. caninum isolates resistant to all classes of anthelmintics, little is known about the frequency and extent of this anthelmintic resistance. The study aim was to evaluate the efficacy of three commercial anthelmintic products in the treatment of foxhound dogs with a history of persistent A. caninum infections. In the first phase of this study, 35 foxhounds were randomly divided into three treatment groups: moxidectin/imidacloprid (MI), pyrantel pamoate/febantel/praziquantel (PFP), and emodepside/praziquantel (EP). Fecal samples were collected on day 0, 11, and 33 post-treatment (PT), and hookworm eggs were quantified using the mini-FLOTAC technique with a multiplication factor of 5 eggs per gram (EPG). The fecal egg count reduction (FECR) on day 11 PT was 65% (95% CI: 62%-68%) for MI, 69% (95% CI: 66%-72%) for PFP, and 96% (95% CI: 94%-97%) for EP. On day 33 PT, the FEC in the MI and PFP groups returned to almost the same values as on day 0, while in the EP group, the FEC remained low. Since MI and PFP proved ineffective, 32 animals were randomly divided into two groups in the second phase. They were treated either with a combination of MI/PFP or EP. The FECR at day 13 PT for the combination MI/PFP was 89% (95% CI: 87%-91%) and 99% (95% CI: 98%-99%) for EP. These results suggest that this A. caninum population is resistant to multiple anthelmintics. Although the combination of MI/PFP improved the anthelmintic efficacy, the FECR remained below 90%. Future studies are indicated to evaluate further the epidemiology of persistent hookworm infections in dogs in the US and to identify more effective treatment protocols as they pose a significant health risk to canine and human health.

Trypanosoma cruzi strain and starvation-driven mitochondrial RNA editing and transcriptome variability.

Trypanosoma cruzi is a unicellular protistan parasitic species that is comprised of strains and isolates exhibiting high levels of genetic and metabolic variability. In the insect vector, it is known to be highly responsive to starvation, a signal for progression to a life stage in which it can infect mammalian cells. Most mRNAs encoded in its mitochondrion require the targeted insertion and deletion of uridines to become translatable transcripts. This study defined differences in uridine-insertion/deletion RNA editing among three strains and established the mechanism whereby abundances of edited (and, thus, translatable) mitochondrial gene products increase during starvation. Our approach utilized our custom T-Aligner toolkit to describe transcriptome-wide editing events and reconstruct editing products from high-throughput sequencing data. We found that the relative abundance of mitochondrial transcripts and the proportion of mRNAs that are edited varies greatly between analyzed strains, a characteristic that could potentially impact metabolic capacity. Starvation typically led to an increase in overall editing activity rather than affecting a specific step in the process. We also determined that transcripts CR3, CR4, and ND3 produce multiple open reading frames that, if translated, would generate different proteins. Finally, we quantitated the inherent flexibility of editing in T. cruzi and found it to be higher relative to that in a related trypanosomatid lineage. Over time, new editing domains or patterns could prove advantageous to the organism and become more widespread within individual transcriptomes or among strains.

A link between mitochondrial gene expression and life stage morphologies in Trypanosoma cruzi.

The protozoan Trypanosoma cruzi has a complicated dual-host life cycle, and starvation can trigger transition from the replicating insect stage to the mammalian-infectious nonreplicating insect stage (epimastigote to trypomastigote differentiation). Abundance of some mature RNAs derived from its mitochondrial genome increase during culture starvation of T. cruzi for unknown reasons. Here, we examine T. cruzi mitochondrial gene expression in the mammalian intracellular replicating life stage (amastigote), and uncover implications of starvation-induced changes in gene expression. Mitochondrial RNA levels in general were found to be lowest in actively replicating amastigotes. We discovered that mitochondrial respiration decreases during starvation in insect stage cells, despite the previously observed increases in mitochondrial mRNAs encoding electron transport chain (ETC) components. Surprisingly, T. cruzi epimastigotes in replete medium grow at normal rates when we genetically compromised their ability to perform insertion/deletion editing and thereby generate mature forms of some mitochondrial mRNAs. However, these cells, when starved, were impeded in the epimastigote to trypomastigote transition. Further, they experience a short-flagella phenotype that may also be linked to differentiation. We hypothesize a scenario where levels of mature RNA species or editing in the single T. cruzi mitochondrion are linked to differentiation by a yet-unknown signaling mechanism.

Trypanosoma vivax infection in sheep: Different patterns of virulence and pathogenicity associated with differentially expressed proteomes.

Cattle trypanosomosis caused by Trypanosoma vivax is a widely distributed disease in Africa and Latin America. It causes significant losses in the livestock industry and is characterized by fluctuating parasitemia, anemia, fever, lethargy, and weight loss. In this study we evaluated the virulence (capacity to multiply inside the host and to modulate the host response) and pathogenicity (ability to produce disease and/or mortality) patterns of two T. vivax strains (TvMT1 and TvLIEM176) in experimentally-infected sheep and determined the proteins differentially expressed in the proteomes of these two strains. Hematological and clinical parameters were monitored in experimentally-infected versus non-infected sheep for 60 days. All the infected animals developed discernable parasitemia at 3 days post-infection (dpi), and the first parasitemia peak was observed at 6 dpi. The maximum average value of parasitemia was 1.3×107 (95% CI, 7.9×105-2×108) parasites/ml in TvLIEM176-infected animals, and 2.5×106 (95% CI, 1.6×105-4×107) parasites/ml in TvMT1-infected ones. Anemia and clinical manifestations were more severe in the animals infected by TvMT1 strain than in those infected by TvLIEM176. In the proteomic analysis, a total of 29 proteins were identified, of which 14 exhibited significant differences in their expression levels between strains. Proteins with higher expression in TvLIEM176 were: alpha tubulin, beta tubulin, arginine kinase, glucose-regulated protein 78, paraflagellar protein 3, and T-complex protein 1 subunit theta. Proteins with higher expression in TvMT1 were: chaperonin HSP60, T-complex protein 1 subunit alpha, heat shock protein 70, pyruvate kinase, glycerol kinase, inosine-5'-monophosphate dehydrogenase, 73kDa paraflagellar rod protein, and vacuolar ATP synthase. There was a difference in the virulence and pathogenicity between the T. vivax strains: TvLIEM176 showed high virulence and moderate pathogenicity, whereas TvMT1 showed low virulence and high pathogenicity. The proteins identified in this study are discussed for their potential involvement in strains' virulence and pathogenicity, to be further defined as biomarkers of severity in T. vivax infections.

Trypanosoma vivax infection in sheep: Different patterns of virulence and pathogenicity associated with differentially expressed proteomes.

Cattle trypanosomosis caused by Trypanosoma vivax is a widely distributed disease in Africa and Latin America. It causes significant losses in the livestock industry and is characterized by fluctuating parasitemia, anemia, fever, lethargy, and weight loss. In this study we evaluated the virulence (capacity to multiply inside the host and to modulate the host response) and pathogenicity (ability to produce disease and/or mortality) patterns of two T. vivax strains (TvMT1 and TvLIEM176) in experimentally-infected sheep and determined the proteins differentially expressed in the proteomes of these two strains. Hematological and clinical parameters were monitored in experimentally-infected versus non-infected sheep for 60 days. All the infected animals developed discernable parasitemia at 3 days post-infection (dpi), and the first parasitemia peak was observed at 6 dpi. The maximum average value of parasitemia was 1.3 × 107 (95% CI, 7.9 × 105-2 × 108) parasites/ml in TvLIEM176-infected animals, and 2.5 × 106 (95% CI, 1.6 × 105-4 × 107) parasites/ml in TvMT1-infected ones. Anemia and clinical manifestations were more severe in the animals infected by TvMT1 strain than in those infected by TvLIEM176. In the proteomic analysis, a total of 29 proteins were identified, of which 14 exhibited significant differences in their expression levels between strains. Proteins with higher expression in TvLIEM176 were: alpha tubulin, beta tubulin, arginine kinase, glucose-regulated protein 78, paraflagellar protein 3, and T-complex protein 1 subunit theta. Proteins with higher expression in TvMT1 were: chaperonin HSP60, T-complex protein 1 subunit alpha, heat shock protein 70, pyruvate kinase, glycerol kinase, inosine-5'-monophosphate dehydrogenase, 73 kDa paraflagellar rod protein, and vacuolar ATP synthase. There was a difference in the virulence and pathogenicity between the T. vivax strains: TvLIEM176 showed high virulence and moderate pathogenicity, whereas TvMT1 showed low virulence and high pathogenicity. The proteins identified in this study are discussed for their potential involvement in strains' virulence and pathogenicity, to be further defined as biomarkers of severity in T. vivax infections.

Prevalencía de helmintos gastrointestinales en gatos admitidos en la policlínica veterinaria de la Universidad del Zulia / Prevalence of gastrointestinal helminths in cats admitted at the veterinary policlinic

Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos gastrointestinales en gatos (Felis catus) que asistieron al Servicio de Consulta Externa de la Policlínica Veterinaria de la Universidad del Zulia (PVU), durante el período de enero a diciembre 2004. Para ello se recolectaron directamente del recto, heces de 64 gatos, procesándose mediante el método de flotación fecal con solución salina saturada, obteniéndose una prevalencia general de helmintos gastrointestinales de 46,9%. Los helmintos observados fueron Ancylostoma spp. (29,7 por ciento), Trichuris spp. (10,9 por ciento), Toxocara spp. (7,8 por ciento) y Physaloptera spp. (6,3 por ciento). No se observaron diferencias estadísticamente significativas de los valores de prevalencia entre sexos (42,9 por ciento en hembras y 50 por ciento en machos), ni entre grupos raciales (48,1 por ciento en gatos mestizos y 41,7 por ciento en gatos de razas puras). En referencia a los grupos etarios, la prevalencia general fue: animales menores de 1 año, 52,6 por ciento; entre 1 y 2 años, 50 por ciento; entre 2 y 4 años, 35,7 por ciento y mayores de 4 años, 47,1 por ciento, sin observarse diferencias estadísticamente significativas (P>0,05) entre los grupos. Toxocara spp. sólo se observó en animales menores de 1 año de edad y Trichuris spp. se detectó en animales mayores de 2 años.

This investigation was carried out in order to determinate the prevalence of gastrointestinal helminths in cats (Felis catus) attended at the Veterinary Policlinic of the University of Zulia (PVU), during the period of January to December 2004. Fecal samples were collected directly from the rectum of 64 cats, and then were processed by the method of fecal flotation with saturated saline solution, obtaining a general prevalence of gastrointestinal helminths of 46.9%. The following helminths were observed: Ancylostoma spp. (29.7%), Trichuris spp. (10.9%), Toxocara spp. (7.8%) and Physaloptera spp. (6.3%). Significant statistical differences of the prevalence values were not observed among sex (42.9% in females and 50% in males) neither among racial groups (48.1% in mixed-breed cats and 41.7% in pure-breed cats). General prevalence in cats by age was: cats younger than 1 year old, 52.6%; between 1 and 2 years, 50%; between 2 and 4 years, 35.7%; and older than 4 years old, 47.1%. Statistical differences were not observed between ages. Toxocara spp. was only found in animals younger than 1 year old and Trichuris spp. was detected in animals older than 2 years.

Garrapatas (Acari: Ixodidae) recolectadas de caninos bajo asistencia veterinaria en Maracaibo Venezuela / Ticks (Acari: Ixodidae) collected from canin es under veterinary care in Maracaibo Venezuela

Se planificó la presente investigación con la finalidad de identificar las garrapatas que parasitan a caninos que asisten al servicio de consulta externa de la Policlínica Veterinaria Universitaria de la Universidad del Zulia (PUV-LUZ) en Maracaibo, Venezuela. Para esto, se muestrearon 624 garrapatas recolectadas de 64 caninos, las cuales fueron identificadas siguiendo las claves correspondientes. El total de garrapatas recolectadas fueron identificadas como la especie Rhipicephalus sanguineus. El promedio de la intesidad de infestación fue de 9,8 garrapatas por animal (rango: 2-55). De acuerdo al sexo de la garrapata, se recuperaron 366 hembras y 258 machos. La relación sexual (macho:hembra) fue de 1:1.4. En cuanto al sexo del hospedador, las garrapatas fueron recuperadas de 33 (51 por ciento) machos y 31 (48,4 por ciento) hembras. De acuerdo a la edad del hospedador, se recolectaron garrapatas de 50 (78,1 por ciento) animales menores de un año de edad y de 14 (21,9 por ciento) caninos mayores de un año. Por otra parte, de acuerdo a la raza del canino, se obtuvieron garrapatas de 31 (48,4 por ciento) animales de razas puras y de 33 (51,6 por ciento) caninos mestizos. No se detectaron diferencias estadísticas entre la infestación de acuerdo a las variables estudiadas. La única especie identificada fue R. sanguineus, con un grado bajo infestación.

A survey was carried out to identify ticks infesting dogs presented to Veterinary Policlinic of The University of Zulia (PVU-LUZ) in Maracaibo, Venezuela. For this, were collected 624 ticks from 64 dogs, those were identified. All of them were identified as Rhipicephalus sanguineus. The mean intensity was 9.8 ticks per dog (range: 2-55). Were collected 366 ticks female and 258 ticks male. Sexual ratio (male:female) was 1:1.4. There were 33 (51.69%) male dogs parasitized and 31 (48.4%) female dogs. Infestation by age was more common in dogs younger than 1 year old (78.1%) than older dogs (21.9%). Thirty-one (48.4%) pure-breed dogs were infested while mixed-breed dogs were 33 (51.6%). Statistical differences were not detected among the infestation according to sex, age or breed of the hosts. The only identified specie was R. sanguineus with a low mean intensity.

Prevalencia y dinámica de hpg mensual de fasciola hepatica y otros helmintos en un rebaño bovino de una zona inundable tropical. / Prevalence and Monthly EPG Dinamic of Fasciola hepatica and Others Helminths in a Bovine Herd From a Tropical Swamp Zone.

Con el propósito de estimar la prevalencia y los valores de HPG mensuales de Fasciola hepatica y otros helmintos gastrointestinales en un rebaño bovino localizado en el sector Playa Bonita del municipio Mara, estado Zulia, Venezuela, se realizó un muestreo coprológico a 242 vacas, a través de técnicas cuantitativas (McMaster modificada, sedimentación). Para F. hepatica, el valor medio de prevalencia anual fue 23% y durante el estudio osciló entre 0 y 54,5%, observándose una relación significativa con los meses del año (P<0,01); la abundancia media de HPG mostró un rango de 0 a 6,5 HPG, mientras su intensidad media estuvo entre 0 y 16,1 HPG. Para Cotylophoron cotylophorum y los nematodos estrongilados hallados, la prevalencia media anual fue 56,8 y 16,3%, las mensuales fluctuaron entre 31,2-73,9 y 0-34,7%, el rango de abundancia media 3,0-37,8 y 0-18,1 HPG, y el de intensidad media 9,6-52 y 0-87,5 HPG, respectivamente. Hubo una relación significativa entre la prevalencia de nematodos estrongilados y los meses del año (P<0,05) y un efecto de estos últimos sobre sus abundancias medias de HPG (P<0,05). Los resultados muestran valores epidemiológicos de moderados a altos, indicando un papel importante del ganado adulto en el mantenimiento de estas helmintosis en el rebaño. La relación de las variables estudiadas con los meses del año fue determinada, dando la posibilidad de diseñar tratamientos estratégicos como medida de control.

In order to estimate the prevalence and the monthly EPG values of Fasciola hepatica and others gastrointestinals helmints in a bovine herd, located in the Playa Bonita sector of the Mara Municipality, Zulia State, Venezuela; were taken 242 coprologics samples from cows, which were analized with quantitatives technics (modified McMaster and sedimentation). The mean value of annual prevalence to F. hepatica was 23% and the rank during the study was 0-54.5%, being observed a significative relationship with the month of the year (P<0.01); the EPG mean abundance showed a range since 0 to 6.5, while it’s mean intensity was between 0 and 16.1 EPG. The annual prevalence of Cotylophoron cotylophorum and the nematodes found, were 56.8 and 16.3% and the monthly ones fluctuated between 31.2-73.9 and 0-34.7%, the range of EPG abundance 3.0-37.8 and 0-18.1 and it’s mean intensity 9.6-52 and 0-87.5, respectively. Had an effect and significative relationship of the month of the year on the prevalence and abundance of gastrointestinals nematodes (P<0.05). The results showed of moderate to high values, indicative of a mainly role of mature livestock in the maintenance of these helminthosis in the herd. The relationship of these variables with the months of the year was determined, giving the possibility to use strategic treatments as control measure of these diseases.

Prevalence of intestinal parasites in dogs under veterinary care in Maracaibo, Venezuela.

The prevalence of intestinal parasites in dogs presented to the Veterinary Policlinic of the University of Zulia (PVU) was measured between January and December 2001. A total of 614 fecal samples were evaluated by the fecal flotation method. One or more species of parasites was identified in 218 (35.5%) dogs. The parasites most frequently detected were: Ancylostoma spp. (24.5%), Toxocara canis (11.4%) and Isospora spp. (8.1%). Single parasitic infections were present in 149 (24.3%) dogs. The age distribution of intestinal parasites in dogs less than 1 year old had a higher overall prevalence than those dogs over 12 months of age. There was no significant difference in the prevalence between male (38.9%) and female (31.7%) dogs. There was a significantly (P < 0.05) greater prevalence of parasites in mixed-breed dogs (40.3%) as compared with pure-breed dogs (30.8%). A significant difference (P < 0.05) was detected between the general prevalence of January and December compared to August.