Fernando I. Puerto

Serologic Evidence of West Nile Virus Infection in Horses, Yucatan State, Mexico

Serum samples were obtained from 252 horses in the State of Yucatan, Mexico, from July to October 2002. Antibodies to West Nile virus were detected by epitope-blocking enzyme-linked immunosorbent assays in three (1.2%) horses and confirmed by plaque reduction neutralization test. We report the first West Nile virus activity in the State of Yucatan.

Prevalencia de infección por el virus del Nilo Occidental en dos zoológicos del estado de Tabasco

Objective. To determine the prevalence of West Nile Virus (WNV) infection in animals, mosquitoes and employees from two zoos of Tabasco state, Mexico. Material and Methods. WNV antibodies were detected by blocking ELISA in serum samples from animals. Viral RNA was detected by RT-PCR from mosquitoes and serum samples from employees at “Yum-Ka” zoo. Results. Seroprevalence in birds was 25.65% (19/74) and 85% (6/7) in reptiles from “La Venta” zoo. Thirty-one percent of birds (50/160) and 34.48% mammals (16/29) at the “Yum-Ka” zoo, were seropositive. All human serum samples from Yum-ka zoo were negative by RT-PCR. A pool of mosquitoes (Culex quinquefasciatus) was positive for WNV. Conclusions. The presence of WNV antibodies in animals from both zoos and the detection of viral genome in mosquitoes demonstrate the presence of WNV in this region and indicates a potential risk of infection in animals and humans.

Antibodies to influenza and West Nile viruses in horses in Mexico

INFLUENZA A virus (IAV) (family Orthomyxoviridae) is a highly infectious respiratory pathogen of birds and mammals, including human beings and horses ([Palese and Shaw 2007][1]). The virus is classified into different subtypes based on the antigenic properties of the haemagglutinin (HA) and

Ecological Niche Model for Predicting Distribution of Disease-Vector Mosquitoes in Yucatán State, México

Abstract The majority of the Yucatán State, México, presents subtropical climate that is suitable for many species of mosquitoes that are known to be vectors of diseases, including those from the genera Aedes and Culex. The objective of this study is to identify the geographic distribution of five species from these two genera and estimate the human population at risk of coming in contact with them. We compiled distributional data for Aedes aegypti (L.), Aedes (Howardina) cozumelensis (Diaz Najera), Culex coronator Dyar and Knab, Culex quinquefasciatus Say, and Culex thriambus Dyar from several entomological studies in Yucatán between March 2010 and September 2014. Based on these data, we constructed ecological niche models to predict the spatial distribution of each species using the MaxEnt algorithm. Our models identified areas with suitable environments for Ae. aegypti in most of Yucatán. A similar percentage of urban (97.1%) and rural (96.5%) populations were contained in areas of highest suitability for Ae. aegypti, and no spatial pattern was found (Morans I = 0.33, P = 0.38); however, we found an association of abundance of immature forms of this species with annual mean temperature (r = 0.19, P≤0.001) and annual precipitation (r = 0.21, P≤0.001). Aedes cozumelensis is also distributed in most areas of the Yucatán State; Cx. quinquefasciatus, Cx. coronator, and Cx. thriambus are restricted to the northwest. The information generated in this study can inform decision-making to address control measures in priority areas with presence of these vectors.

First histopathological study in kidneys of rodents naturally infected with Leptospira pathogenic species from Yucatan, Mexico

OBJECTIVE To report the renal histological lesions in synanthropic rodents, Mus musculus and Rattus rattus, naturally infected with Leptospira spp., captured in a rural community in Yucatan, Mexico. METHODS Kidney samples of synanthropic rodents were collected from a rural community in Yucatan, Mexico. Polymerase chain reaction was used to detect Leptospira spp. infection. Tissue kidney was fixed in 10% buffered formalin, processed according to the usual techniques for paraffin inclusion, cut and stained with hematoxylin and eosin, and examined using a conventional electronic microscope. RESULTS A total of 187 rodents were captured. Nine individuals (4.8%) were positive for Leptospira spp. in the molecular analysis. All renal lesions observed in the histopathological study had been reported previously for Leptospira spp. infection. CONCLUSIONS The histopathological lesions are present in the kidneys, plus the results of the polymerase chain reaction confirm that these rodents are true carriers of Leptospira spp.

Detección molecular de leptospiras patógenas en roedores sinantrópicos y silvestres capturados en Yucatán, México

Introduction: Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira, which is endemic in México and considered a public and veterinary health problem. Rodents are the most relevant reservoirs of Leptospira spp. because the bacteria establish and reproduce in its renal tissue and are excreted through the urine. Objective: To identify the presence of Leptospira spp. in renal tissue from rodents captured in Yucatán, México. Materials and methods: Synanthropic and wild rodents were captured in the rural municipality of Cenotillo, Yucatán, México. We collected one kidney from each rodent and extracted the total DNA. The identification of Leptospira spp. was done by detecting two fragments of the 16S rRNA gene using end-point polymerase chain reaction (PCR). We sequenced and analyzed positive products using alignment tools. Results: A total of 92 rodents belonging to seven different species were captured. The PCR yielded a global positivity of 5.4% (5/92). The alignment analysis of the sequenced products demonstrated a 100% of coverage and identity with Leptospira interrogans. This is the first molecular evidence of Leptospira spp. circulation in Heteromys gaumeri captured in Yucatán, México. Conclusion: Our results evidenced that rodents of Yucatán are reservoirs of Leptospira spp. and participate in the infection cycle of leptospirosis in the region.

Absence of molecular evidence of Leptospira spp. in urine samples collected from rodents captured in Yucatán, México

espanolRESUMEN. Leptospira spp. es una bacteria espiroqueta, agente causal de la leptospirosis, enfermedad zoonotica endemica en Mexico que representa un serio problema de salud publica y veterinaria. Los roedores son reconocidos como los mas importantes reservorios de la bacteria, la cual es transmitida principalmente por contacto directo o indirecto con Leptospira spp. contenidas en orina de individuos infectados. El objetivo de este estudio fue evaluar la circulacion de Leptospira spp. en muestras de orina de roedores silvestres y sinantropicos de Yucatan, Mexico. Ochenta y cuatro roedores fueron capturados en la comunidad de Cenotillo, Yucatan. Se recolectaron 26 muestras de orina de la vejiga y fueron usadas en la extraccion de ADN total. La identificacion de Leptospira spp. se pretendio por medio de la prueba de reaccion en cadena de la polimerasa en su variante punto final. No se encontro evidencia de Leptospira spp. en las muestras de orina. Es necesario emplear otros tejidos para la identificacion de Leptospira spp. antes de concluir que los roedores usados en el presente estudio no son reservorios de esta bacteria. EnglishABSTRACT. Leptospira spp. is a spirochete bacteria, causal agent of leptospirosis, zoonotic disease endemic in Mexico that represents a serious public health and veterinary problem. Rodents are recognised as the most important reservoirs of this bacteria, which is transmitted mainly through direct or indirect contact with the Leptospira spp. excreted in the urine of infected individuals. The aim of this study was to evaluate the circulation of Leptospira spp. in urine samples of wild and synanthropic rodents from Yucatan, Mexico. Eighty-four rodents were captured in the community of Cenotillo, Yucatan. Twenty-six urine samples were collected from the bladder and were used in the total DNA extraction. The identification of Leptospira spp. was intended through the polymerase chain reaction test in its endpoint variant. No evidence of Leptospira spp. was found in the urine samples. It is necessary to use other tissues for the identification of Leptospira spp., before concluding that the rodents used in the present study are not reservoirs of this bacteria.

New Records of Ectoparasites Echinolaelaps echidninus and Polyplax spinulosa on Rodents with Serological Evidence of Flavivirus Infections at Mérida, Yucatán, México

Abstract. Two ectoparasites, spiny rat mite, Echinolaelaps echidninus (Berlese) (n = 27), and spined rat louse, Polyplax spinulosa (Burmeister) (n = 2), were recorded for the first time in Yucatán State and documented with photographs. The ectoparasites were identified mostly on black rat, Rattus rattus (L.), with serological evidence of flavivirus infection. Adult female E. echidninus was most common and found on black rat with serological evidence of yellow fever, Modoc, and Apoi viruses. We also reported for the first time the cat flea, Ctenocephalides felis (Bouché), on R. rattus. We discussed the potential for the arthropods to bite and transmit pathogens to humans.

Estudio serológico del virus de la Enfermedad de Borna en pacientes esquizofrénicos de Yucatán, México

Antecedentes. El Virus de la Enfermedad de Borna (VEB) es un virus envuelto, con una cadena de RNA simple de polaridad negativa. VEB causa enfermedad a nivel del Sistema Nervioso Central en muchos animales vertebrados, que frecuentemente se manifiesta como anormalidades en la conducta. La infeccion silvestre con el VEB ocurre de manera natural. De hecho fue detectada primero en caballos y en ovejas en algunas regiones de Europa Central. Los resultados serologicos obtenidos de diferentes laboratorios en los ultimos 15 anos y recientemente con la biologia molecular, muestran que el VEB puede infectar a los seres humanos y que tambien puede estar asociado a ciertos trastornos psiquiatricos. Reportamos el primer estudio de seroprevalencia del VEB en humanos de Latinoamerica. Metodologia. Muestras de suero fueron obtenidas de 70 pacientes con diagnostico de esquizofrenia y otras 70 muestras de suero se tomaron de personas sanas que participaron de manera voluntaria al estudio y que fueron pareados por edad, sexo y nivel socioeconomico. Las muestras de ambos grupos fueron procesadas para analizar por Western-blot en nuestro laboratorio y en The Scripps Research Institute en San Diego, CA USA. Como antigeno se utilizo a la fosfoproteina (P) obtenida de la expresion con GSTP. Resultados. El grupo de pacientes esquizofrenicos, fueron 47 hombres y 23 mujeres con un promedio de edad de 40 anos (rango de 17 a 73 anos). Todos ellos nacieron en la Peninsula de Yucatan. Para su clasificacion el diagnostico se baso en el ICD-10. El estudio mostro una prevalencia de anticuerpos en los sueros contra la proteina GST-P de 21.43% (15/70), mientras que no se encontraron anticuerpos en el suero de las personas sanas. No se encontro relacion entre el genero, la edad y tipo de esquizofrenia y la presencia de anticuerpos contra VEB. Conclusiones. Hasta donde sabemos, este es el primer estudio en Latinoamerica que se lleva a cabo para detectar anticuerpos contra el VEB en seres humanos. Nuestros resultados son semejantes a lo reportado en la literatura y apoyan la posible asociacion entre la presencia de anticuerpos contra el VEB y los trastornos psiquiatricos. Sin embargo, se necesita continuar con mas estudios para conocer si es realmente un problema de salud y cual podria ser su magnitud.

Evidencia serológica de la infección por el Virus del Oeste del Nilo en caballos del estado de Yucatán, México

Se obtuvieron muestras de suero de 252 caballos en el estado de Yucatan, Mexico, de julio a octubre de 2002. Se determinaron en ellos anticuerpos contra el virus del Oeste del Nilo a traves del bloqueo de epitopes por ensayo inmunoenzimatico. Se observo serorreactividad en 3 (1.2%) caballos. Los resultados fueron confirmados a traves de la reduccion de neutralizacion de placas. Este es el primer reporte que demuestra la presencia del virus del Oeste del Nilo en el estado de Yucatan, Mexico.