Andrés F. Londoño

Prevalence of Leptospira spp. in Urban Rodents from a Groceries Trade Center of Medellín, Colombia

Leptospirosis is a widely distributed zoonosis, and rats are its most common source of infection. Our goal was to determine the frequency for Leptospira infection in rodents in a farmers market in the city of Medellin. We performed a descriptive transversal study sampling 254 rodents. Rodents were bled and killed, and kidneys samples were taken. Supernatants of macerated kidneys were cultured on Fletcher medium. Microagglutination tests (MATs) with 11 serovars were also carried out in rat serum, and a polymerase chain reaction (PCR) specific for pathogenic species was used to test each bacterial culture. All animals were identified as Rattus norvegicus; 25% and 20% were positive by MAT and culture, respectively. PCR tests of 12 isolates were positive for pathogenic serovars, and 4 of them were confirmed as L. interrogans by sequencing. These data show the role of this natural carrier and shedder of pathogenic leptospires in the epidemiology of urban leptospirosis in Colombia.

Genetic Evidence of Hantavirus Infections in Wild Rodents from Northwestern Colombia

This report builds on recent serological evidence for the presence of hantavirus in northern Colombia by providing sequence-specific and phylogenetic data of hantavirus infections in wild rodents. From August 2007 to August 2008, 354 rodent specimens representing four families were collected in the northwestern Antioquia region of Colombia. Antibodies reactive to Sin Nombre virus and Maciel virus antigens by IgG enzyme-linked immunosorbent assay were found in 15 of 109 (14%) Cherries cane rats (Zygodontomys cherriei), the only sigmodontinae rodents captured. Lung tissue samples from 11 of the 15 seropositive rodents were RT-polymerase chain reaction positive for hantavirus RNA, using primers for the S and M genome segments. Eight of these amplicons were sequenced and phylogenetic analyses indicated RNA of a hantavirus closely related to Calabazo virus, previously found in Panama. This is the first report of the genetic characterization of a hantavirus in rodents in Colombia.

Human prevalence of the spotted fever group (SFG) rickettsiae in endemic zones of Northwestern Colombia

In February 2006, an outbreak of human rickettsiosis occurred in the municipality of Necoclí Colombia, with 35% of lethality. This episode was, followed by two more, one in the municipality of Los Cordobas in 2007 with a 54% of lethality and the other one in the municipality of Turbo in 2008 with 27% of lethality. The aim of this study was to perform serological tests in healthy persons to determine the seroprevalence of antibodies against spotted fever group (SFG) rickettsiae and develop a survey to study some infection risk-related factors. A cross-sectional study was performed in 2011 and 2012. A blood sample and survey of associated factors was performed in healthy persons. A prevalence of 32%-41% was found in healthy people. From the multivariate analysis, we found that people living more than 16 years in these sites had a 79% higher risk of being seropositive and a 46% higher risk when they reported having birds in their houses if the variable of having a horse was included in the model. In conclusion, this study shows endemicity of at least one spotted fever group Rickettsia in the study zone.

Evidencia serológica de circulación de Leptospira spp en Rattus norvegicus naturalmente expuestos en una zona urbana colombiana

Objetivo Determinar la frecuencia de anticuerpos dirigidos contra especies de Leptospira patogenas en reservorios naturales, con el proposito de establecer evidencia de su papel potencial en la dispersion ambiental de Leptospira y por consiguiente su actuacion como agente diseminador de la infeccion tanto al humano como a otras especies susceptibles. Materiales y metodos El muestreo se llevo a cabo en la Plaza Minorista durante el periodo comprendido entre agosto de 2006 y abril de 2007, en el cual se capturaron 254 roedores Rattus norvegicus. Se obtuvo sangre de estos por puncion cardiaca y el suero resultante se proceso con la prueba de Microaglutinacion. Resultados El analisis serologico para verificar las serovariedades circulantes de Leptospira spp, dio como resultado que 64 roedores (25,2 %, 95 % CI=19,5-30,1) tuvieron titulos positivos para al menos una de las 11 serovariedades probadas. Conclusiones Los datos muestran que no solo la serovariedad Icterohaemorrhagiae esta asociada con esta especie reservoria; tambien lo estan otras serovariedades como Grippothyphosa y Canicola. El estudio permitio determinar la frecuencia de anticuerpos contra especies patogenas de Leptospira para reservorios procedentes de una zona urbana colombiana. Estos datos son relevantes para las entidades de salud publica por constituir la base para la implementacion de campanas de control adecuadas para esta zona del pais y como modelo de otros estudios similares en otras ciudades colombianas.OBJECTIVE Assessing the frequency of antibodies directed against pathogenic Leptospira species found in natural reservoirs for establishing evidence of their potential role in the environmental dispersion of Leptospira and consequent dissemination of the infection to humans as well as to other susceptible species. MATERIAL AND METHODS A survey was carried out in the Plaza Minorista from August 2006 to April 2007 in which 254 rats (Rattusnorvegicus) were captured. Blood was obtained from these rodents by cardiac puncture and the resulting serum was used for microagglutination tests. RESULTS Serological analysis for verifying Leptospira spp circulating serovars resulted in 64 rodents (25.2 %;19.5-30.1 95 %CI) having positive antibody titres for at least 11 of the serovars tested. CONCLUSIONS Frequency data regarding the antibodies so detected showed that the Icterohaemorrhagiae serovar was not the only one possibly associated with this reservoir species, but also with others such as the Grippothyphosa and Canícolaserovars. The study determined the frequency of antibodies against pathogenic Leptospira species for reservoirs from an urban area in Colombia. This data is relevant for public health authorities and might constitute the basis for implementing appropriate control campaigns for this area of the country and, likewise, this work could serve as a model for similar studies in other Colombian cities.

Epidemiological Surveillance of Rodent-Borne Viruses (Roboviruses)

This article will outline surveillance approaches for rodent-borne viruses (roboviruses). We present a synopsis of the main categories of trapping methods with some notes about their use in fieldwork. We also describe the types of laboratory analysis commonly used in Robovirus surveillance.

Primera evidencia de infección por el virus de la coriomeningitis linfocítica (arenavirus) en roedores Mus musculus capturados en la zona urbana del municipio de Sincelejo, Sucre, Colombia

INTRODUCTION The lymphocytic choriomeningitis virus is an Old World arenavirus that infects Mus musculus, and can cause congenital hydrocephalus, chorioretinitis and multisystemic failure in transplant human recipients. Although the disease has not been clinically diagnosed in Colombia yet, there have been reports of infection with the Pichindé virus in rodents from Cauca and Valle del Cauca departments, and with the Guanarito virus in rodents from Córdoba department. OBJECTIVE To identify the lymphocytic choriomeningitis virus from Mus musculus captured in the municipality of Sincelejo. MATERIALS AND METHODS We evaluated 80 samples of plasma by ELISA using antigen from lymphocytic choriomeningitis virus. Additionally, a nested RT-PCR was performed to seropositive and seronegative samples for the S-segment. RESULTS We found a 10% seroprevalence (8/80) and the viral genome was detected in 16 brain samples; the alignment (BLAST) and the phylogenetic analysis (MrBayes, version 3.2.2) confirmed the presence of the lymphocytic choriomeningitis virus. CONCLUSION The results indicated that human infection with the lymphocytic choriomeningitis virus in humans could occur in the urban area of Sincelejo, although no cases have been reported so far.Introduccion. El virus de la coriomeningitis linfocitica es un arenavirus del Viejo Mundo que se hospeda en el raton casero ( Mus musculus ), y puede causar infecciones congenitas, hidrocefalia, coriorretinitis y falla organica multiple en pacientes receptores de trasplantes. En Colombia aun no se ha reportado la enfermedad mediante diagnostico clinico, pero en estudios serologicos se ha detectado la infeccion por el virus Pichinde en roedores en los departamentos del Cauca y Valle del Cauca, y por el virus Guanarito, en roedores en Cordoba. Objetivo. Detectar el virus de la coriomeningitis linfocitica en M. musculus en el municipio de Sincelejo. Materiales y metodos. Se evaluaron 80 muestras de plasma mediante la prueba ELISA usando antigeno del virus de la coriomeningitis linfocitica. Ademas, se empleo la reaccion en cadena de la polimerasa con transcriptasa inversa (RT-PCR) anidada en muestras de animales seropositivos y seronegativos para la deteccion del segmento S. Resultados. Se encontro una seroprevalencia de 10% (8/80) y se detecto el genoma viral en 16 muestras de cerebro; el alineamiento (en la Basic Local Alignment Search Tool, BLAST) y el analisis filogenetico (mediante el programa MrBayes, version 3.2.2) confirmaron que correspondia al virus de la coriomeningitis linfocitica. Conclusion. Los resultados indicaron que la infeccion por el virus de la coriomeningitis linfocitica en humanos podria ocurrir en el area urbana de Sincelejo, aunque hasta la fecha no se hayan reportado casos.