Detection and genotypes of Toxoplasma gondii DNA in feces of domestic cats in Colombia.

The high prevalence of Toxoplasma gondii in the human population in Colombia has been linked to the existence of a high density of urban stray cats, exposing the whole population to a high density of oocysts. The goal of this study was to determine the DNA prevalence of T. gondii by conventional PCR and to phylogenetically analyze ROP18 sequences from positive samples in domestic cat (Felis catus) fecal samples in the city of Armenia, Quindío. Fecal samples from 140 cats were collected from 10 districts around the city. Samples were concentrated using Ritchie's method and analyzed through optical microscopy. Concentrates were used for DNA extraction followed by nested PCR amplification for T. gondii gene B1. PCR for ROP18 was performed on all B1 positive samples; the ROP18 sequences obtained were related to the Archetype I Brazilian and Chinese strains. No oocysts were detected by optical microscopy; however, 17.8% (25/140) B1 and 24% (6/25) ROP18 PCR-positive samples were detected. Phylogenetic analyses showed that isolates clustered into a single group. We assessed whether associations existed between T. gondii positive fecal samples and survey variables such as cat healthcare and socioeconomic characteristics of owners, but no statistically significant associations were found. The presence of T. gondii in cat feces is an important factor contributing to the high prevalence in the human population of this city.

TITLE: Détection d'ADN et génotypes de Toxoplasma gondii dans les fèces de chats domestiques en Colombie. ABSTRACT: La forte prévalence de Toxoplasma gondii dans la population humaine en Colombie a été liée à l'existence d'une forte densité de chats errants urbains, exposant l'ensemble de la population à une forte densité d'oocystes. Le but de ce travail était de déterminer la prévalence de l'ADN de T. gondii par PCR conventionnelle et d'analyser phylogénétiquement les séquences ROP18 d'échantillons positifs dans des échantillons fécaux de chat domestique (Felis catus) dans la ville d'Armenia, Quindío. Des échantillons fécaux de 140 chats ont été collectés dans 10 districts de la ville. Les échantillons ont été concentrés en utilisant la méthode de Ritchie et analysés par microscopie optique. Des concentrés ont été utilisés pour l'extraction d'ADN suivie d'une amplification par PCR nichée pour le gène B1 de T. gondii. La PCR pour ROP18 a été réalisée sur tous les échantillons positifs pour B1 ; les séquences ROP18 obtenues étaient apparentées aux souches Archétype I brésiliennes et chinoises. Aucun oocyste n'a été détecté par microscopie optique mais les échantillons étaient positifs par PCR pour 17,8 % (25/140) pour B1 et 24 % (6/25) pour ROP18. Les analyses phylogénétiques ont montré que les isolats formaient un seul groupe. Nous avons évalué s'il existait des associations entre des échantillons fécaux positifs à T. gondii et des variables d'enquête telles que les soins de santé des chats et les caractéristiques socioéconomiques des propriétaires, mais aucune association statistiquement significative n'a été trouvée. La présence de T. gondii dans les excréments de chats est un facteur important contribuant à la forte prévalence dans la population humaine de cette ville.

Coinfections and differential diagnosis in immunocompetent patients with uveitis of infectious origin.

BACKGROUND: Making a definite diagnosis of infectious uveitis is a challenging task because many other infectious, and non-infectious uveitis, may have similar non-specific symptoms and overlapping clinical appearances. Co-infections in immunocompetent patients are not frequently proved with traditional serologic-diagnostic tools. METHODS: Descriptive transversal study, in a Uveitis Service of an Ophthalmology Reference Center, in Bogotá, Colombia, from July 2014 to February 2016. Aqueous humor (AH) and/or vitreous fluid, blood and serum samples were collected from consecutive patients suspected of having infectious uveitis. The diagnosis of ocular toxoplasmosis (OT) was confirmed by the Goldmann-Witmer coefficient (GWC) and by polymerase chain reaction (PCR). Differential diagnosis by PCR in AH was done for viral origin such as Cytomegalovirus (CMV), Herpes simplex virus type 1 (HSV1), Herpes simplex virus type 2 (HSV2), Varicella zoster virus (VZV), Epstein-Barr virus (EBV) and Mycobacterium tuberculosis. RESULTS: In 66 Colombian patients with uveitis of presumed infectious origin: 22 (33.3%) were confirmed as OT, 16 (24.2%) as undetermined OT, five (7.5%) as co-infections and 23 (34.8%) as other uveitis. Toxoplasma coinfection with M. tuberculosis was identified in one case by PCR and in four cases with HSV by GWC. The initial clinical diagnosis changed, after laboratory examination, in 21 cases (31.8%). CONCLUSIONS: Clinical diagnosis can be changed by laboratory examination in a significant proportion of cases of uveitis. Diagnosis of OT should combine the use of PCR and GWC to reach the maximum of confirmation of cases. The use of multiple laboratory methods is necessary to identify co-infections and viral infections that can mimic OT in immunocompetent patients.

Polymerase chain reaction (PCR) in ocular and ganglionar toxoplasmosis and the effect of therapeutics for prevention of ocular involvement in South American setting.

INTRODUCTION: Cases of toxoplasmosis present in South America tend to be more severe than that found in other continents. Here, we present our clinical experience of ocular and ganglionar toxoplasmosis in the use of PCR, and of the treatment to prevent ocular involvement. METHODOLOGY: Retrospective analysis of clinical charts of patients with ocular and lymphadenitic toxoplasmosis at the parasitology and tropical medicine consultation in the "Universidad del Quindio" in Colombia. In total, 91 records of cases with ocular toxoplasmosis and 17 with lymphadenitis that underwent PCR analysis for B1 repeated sequence in blood, were compared to the results of 104 people with chronic asymptomatic toxoplasmosis. In addition, 41 clinical records were included from patients with confirmed toxoplasmic lymphadenitis: 10 untreated, 6 that begun treatment after four months of symptoms, and 25 that were treated during the first four months of symptoms and had a follow-up during at least one year. RESULTS: Patients with ocular toxoplasmosis or lymphadenitis had a higher probability of PCR positivity in peripheral blood than chronic asymptomatic people. There were no cases of retinochoroiditis in 25 patients with toxoplasmic lymphadenitis treated before 4 months of symptoms and followed during at least 12 months. In four out of ten untreated cases, new lesions of retinochoroiditis presented after the symptoms of lymphadenitis. CONCLUSIONS: Toxoplasmosisin South America exhibits different clinical behavior and this influences the laboratory results as well as the need for treatment in the case of lymphadenitis. Clinicians should be aware of the geographical origin of the infection in order to adopt different therapeutic and diagnostic approaches.