Survey of coccidia on commercial broiler farms in Colombia: frequency of Eimeria species, anticoccidial sensitivity, and histopathology.

Avian coccidiosis continues to be one of the costliest diseases of commercial poultry. Understanding the epidemiology of Eimeria species in poultry flocks and the resistance profile to common anticoccidials is important to design effective disease prevention and control strategies. This study examined litter samples to estimate the prevalence and distribution of Eimeria species among broiler farms in 4 geographic regions of Colombia. A total of 245 litter samples were collected from 194 broiler farms across representative regions of poultry production between March and August 2019. The litter samples were processed for oocysts enumeration and speciation after sporulation. End-point polymerase chain reaction (PCR) analysis was conducted to confirm the presence of Eimeria species. Anticoccidial sensitivity was determined with 160 Ross AP males in 5 treatment groups: noninfected, nonmedicated control (NNC), infected, nonmedicated control (INC), infected salinomycin treated (SAL, dose: 66 ppm), infected diclazuril treated (DIC, dose: 1 ppm), and infected methylbenzocuate-Clopidol treated (MET.CLO, dose: 100 ppm), All birds were orally inoculated with 1 × 106 sporulated oocysts using a 1 mL syringe, except for the NNC- group who received 1ml of water.Eimeria spp. were found in 236 (96.3%) out of 245 individual houses, representing 180 (92.8%) out of 194 farms. Eimeria acervulina was the most prevalent species (35.0%) followed by Eimeria tenella (30.9%), Eimeria maxima (20.4%), and other Eimeria spp. (13.6%). However, mixed species infections were common, with the most prevalent combination being mixtures of E. acervulina, E. maxima, E. tenella, and other species in 31.4% of the Eimeria-positive samples. PCR analysis identified E. acervulina, E. maxima, E. tenella, Eimeria necatrix, Eimeria mitis, and Eimeria praecox with variable prevalence across farms and regions. Anticoccidial sensitivity testing of strains of Eimeria isolated from 1 region, no treatment difference (P > 0.05) was observed in final weight (BW), weight gain (BWG) or feed conversion (FCR). For the global resistance index (GI) classified SAL and MET.CLO as good efficacy (85.79 and 85.49, respectively) and DIC as limited efficacy (74.52%). These results demonstrate the ubiquitous nature of Eimeria spp. and identifies the current state of sensitivity to commonly used anticoccidials in a region of poultry importance for Colombia.

Resistance profile and molecular characterization of pyrethroid resistance in a Rhipicephalus microplus strain from Colombia.

Intensive use of chemical acaricides for the control of cattle ticks (Rhipicephalus microplus) has led to the development of multiple acaricide resistance in Colombia. The present study aimed to characterize, using toxicological bioassays and molecular biology techniques, the resistance profile of a tick strain isolated from the Arauca state, Northeast Colombia. Commercial acaricides were used in adult immersion tests to determine its in vitro efficacies. Deltamethrin showed very low activity (4-7.3%), a mixture of cypermethrin and chlorpyrifos had intermediate efficacy (64-75.2%), and ethion presented the highest activity (88.5-100%). A colony (Arauquita strain) was established and larval immersion tests confirmed high resistance level to deltamethrin (241-fold) and susceptibility to ivermectin. A quantitative polymerase chain reaction-high resolution melt technique was used to identify single nucleotide polymorphisms (SNPs) in the para-sodium channel gene. All of the genotyped individuals were mutant, presenting one (n = 7), two (n = 7) or three (n = 9) SNPs previously associated with pyrethroid resistance. Sequencing revealed a novel mutation (F712L), that was found for the first time in R. microplus ticks from South America. This is the first description of mutations associated with pyrethroid resistance in R. microplus from Colombia. The acaricide resistance pattern found in the Arauquita strain is similar to other parts of Colombia.

Epidemiological survey and risk factor analysis on Eimeria infections in calves and young cattle up to 1 year old in Colombia.

A large-scale cross-sectional epidemiological study was conducted to evaluate prevalence, species diversity, and associated risk factors of Eimeria infections in 55 cattle farms across seven states of Colombia, including subtropical and tropical regions. In total, 1333 fecal samples from young animals (< 1 year of age) were examined at a single sampling date from August 2016 to December 2016. Flotation and McMaster techniques were conducted for parasitological investigation. Excreted Eimeria oocysts were allowed to sporulate in vitro and thereafter identified to species level based on morphological and morphometric characteristics. The overall Eimeria prevalence was 75.5% (1006/1333), with no difference observed between age categories. In total, 13 different Eimeria species were identified. The most prevalent species was E. bovis (33.5%), followed by E. auburnensis (12.5%) and E. zuernii (11.9%). Analysis of extrinsic associated risk factors revealed the floor type, feeding system, watering system, and herd size as significant (p < 0.05) risk factors for Eimeria spp. infections. Based on these data, it can be assumed that bovine coccidiosis infections occur ubiquitously in the country and might play an important role especially in its subclinical form by affecting production parameters in conventional cattle management systems.

Molecular detection of Marek's disease virus in feather and blood samples from young laying hens in Colombia.

Marek's disease virus (MDV) is an immunosuppressive pathogen that can cause low production efficiency and high mortality rates in chickens. There is no current information on the MDV serotypes and pathotypes circulating in vaccinated commercial farms in Colombia where the birds are vaccinated in the incubator with Gallid herpesvirus (GaHV-2) and Meleagrid herpesvirus 1 (MeHV-1). Based on that, the main focus of this study was to understand the MDV's infection dynamics for the three known serotypes and to detect wild-virus pathogenic strains in 4-layer poultry farms in Antioquia. Samples of blood, feathers and spleens were collected from three randomly chosen animals according to age category: 1, 15, 30, 60, 90, and 120 days. Quantitative real-time PCR (qPCR) that differentiates between the three serotypes of MDV was used to assess viral loads over time, and phylogenetic analysis of the Meq oncogene was done to compare the strains of MDV with those of known pathogenicity. Meleagrid herpesvirus 1 (MeHV-1) was detected in all blood and feather follicle samples with an average number of genome copies (per 10,000 cells) of 31.44 in blood as expected as a result of vaccination. GaHV-2 was also detected in almost 100% of the blood and feather follicle samples throughout all defined age categories, with an average of 10.65 genome copies in blood samples. Gallid herpesvirus 3 (GaHV-3) was detected in 72% of blood and 84.61% of feather samples, with less than 1 copy per 10,000 cells. Based on the number of 132 bp repeats of the BamHI-H and BamHI-D regions in pooled feather samples, there were 70% (8/25) of attenuated MDV and 30% (17/25) of virulent MDV strains circulating in the farms. Virus isolation was performed successfully from every farm. In conclusion, different strains of MDV are circulating for up to 120 days in layers in Antioquia-Colombia and could be of major impact in poultry health. Keywords: Marek's disease virus (MDV); Antioquia-Colombia; qPCR; PCR; Meq gene phylogeny.

Occurrence of endoparasites in wild Antillean manatees (Trichechus manatus manatus) in Colombia.

The recognized impact of parasites in wildlife populations demands surveillance of endangered species like the Antillean manatees (Trichechus manatus manatus) in Colombia. We conducted a parasitological survey in four rescued sea cows in order to document the parasite diversity of this sirenian in the Caribbean wetland of Colombia and contribute to the molecular characterization of its trematodes. The flukes Chiorchis fabaceus, Nudacotyle undicola and the protozoans Eimeria manatus and E. nodulosa were identified in analysed faecal samples. For C. fabaceus and N. undicola, partial regions of ribosomal RNA genes were amplified and sequenced in order to infer their phylogenetic relations. The current study constitutes a new sirenian host (T. manatus manatus) record for the genus Eimeria and the trematode N. undicola.

Regional report on Angiostrongylus vasorum in Colombia: Genetic similarity to European lineage.

The canine lungworm Angiostrongylus vasorum is considered neglected in South America and was only sporadically reported in dogs and wildlife. Gastropods act as obligatory intermediate hosts for this parasitosis. We here analysed Achatina fulica (African giant snail) populations from 5 regions of Colombia for A. vasorum infections. In total, 609 snails were collected from the departments Antioquia, Valle del Cauca and Putumayo. Angiostrongylus vasorum-infected A. fulica were found in all departments with a total prevalence of 3.9%. Larvae originating from Putumayo were molecularly characterized and identified as the European lineage of A. vasorum. This regional report shows for the first time the presence of A. vasorum in intermediate hosts in Colombia and the European genotype in South America.