Synanthropic rodents as virus reservoirs and transmitters

Abstract This review focuses on reports of hepatitis E virus, hantavirus, rotavirus, coronavirus, and arenavirus in synanthropic rodents (Rattus rattus, Rattus norvegicus, and Mus musculus) within urban environments. Despite their potential impact on human health, relatively few studies have addressed the monitoring of these viruses in rodents. Comprehensive control and preventive activities should include actions such as the elimination or reduction of rat and mouse populations, sanitary education, reduction of shelters for the animals, and restriction of the access of rodents to residences, water, and food supplies.

Diferencia espacial de la incidencia de fiebre hemorrágica argentina y la composición y abundancia de roedores en el ensamble / Spatial difference in the incidence of Argentine Hemorrhagic Fever and composition and abundance of rodents in the assemblage

Resumen La fiebre hemorrágica argentina (FHA) es una enfermedad zoonótica endémica en una amplia zona de la pampa húmeda de Argentina. El agente etiológico es el virus Junin que es mantenido en la naturaleza por el roedor Calomys musculinus y transmitido, principalmente, al humano a través de aerosoles generados de las secreciones y excreciones. Objetivos: Caracterizar la composición y diversidad de los ensambles de pequeños roedores, determinar la abundancia del hospedador C. musculinus y la prevalencia del virus de la FHA en las zonas epidémica, histórica y no endémica de dicha enfermedad en Argentina. Métodos: Para el muestreo de roedores en cada una de las zonas se demarcaron un área central y dos periféricas para 18 localidades de la región central de Argentina (incluyendo las provincias de Córdoba, Buenos Aires y Santa Fe) muestreadas en dos años. Se comparó la abundancia de C. musculinus entre zonas y entre las áreas dentro de cada zona y áreas cercanas entre zonas, utilizando modelos de análisis de varianza anidados. Resultados. Dentro de cada zona, el ensamble de roedores mostró diferencia espacial en la composición específica, diversidad y abundancia de C. musculinus. La zona epidémica registró mayor número de especies y mayor abundancia del hospedador. En zona histórica se capturó el menor número de especies (de roedores) y Akodon azarae fue la más abundante. En zona no endémica la composición del ensamble y la abundancia de C. musculinus variaron entre los dos años. Sólo se detectó infección por virus Junin en C. musculinus correspondientes a la zona epidémica con una prevalencia de 2,7 y 1,1% para los años 2007 y 2008, respectivamente. Conclusión: En este sistema, la abundancia del hospedador estaría afectando la dinámica espacial de este virus, más que la diversidad del ensamble o la presencia de A. azarae.

Background. The Argentine Hemorrhagic Fever (AHF) is a zoonotic disease endemic in a wide area of the humid pampa of Argentina. The etiologic agent is the Junin virus that is maintained in the wild by the rodent Calomys musculinus and transmitted to humans, mainly, through aerosols generated from secretions and excretions. Aims: To characterize and compare the assemblages of small rodent composition and diversity inside the epidemic, historic and non-endemic zone of AHF and to register C. musculinus abundance in each zone and in each area within each zone, registering the prevalence of infection in rodent populations. Method: One central and two peripheral areas were delimited to sample rodents in each zone with different incidence of AHF. Thus, 18 localities were selected to do the sampling in two years. Host abundance between zones and among areas inside each zone and among nearby areas between zones were compared applying nested ANOVA's. Results: In each zone, the rodent assemblage showed differences in composition, diversity and numeric representation of C. musculinus. The epidemic zone was the richest of the three, registering also great host abundance; meanwhile in the historic zone, A. azarae was the dominant numeric species with less number of other species. Regarding the non-endemic zone, the assemblage composition and C. musculinus abundance varied respect the sampled year. Junin virus infection was only detected in C. musculinus individuals corresponding to the epidemic zone, with a prevalence of 2.7 and 1.1% for the years 2007 and 2008, respectively. Conclusion: In this system, the abundance of C. musculinus could be impacting over the pathogen dynamic, rather than the assemblage diversity or the A. azarae presence.

Brote de síndrome pulmonar por hantavirus, Tucumán, Argentina / Outbreak of hantavirus pulmonary syndrome in Tucumán, Argentina

Se describe un brote de síndrome pulmonar por hantavirus en el departamento de Burruyacú, provincia de Tucumán. La detección en 2016 de un caso de hantavirosis en una joven de 23 años -en ese momento considerado el primero ocurrido en dicha provincia- promovió un estudio epidemiológico exhaustivo, que permitió detectar retrospectivamente otro caso ocurrido en un niño de 5 años, un mes antes, en el mismo departamento. La infección fue confirmada por serología en ambos casos (caso 1 en muestras de 4 y 7 días de evolución, caso 2 en muestra a los 4 días). En ambos casos el genotipo viral fue caracterizado como HU39694 y los contactos fueron serológicamente negativos. En las áreas fueron identificados roedores pertenecientes a los géneros Akodon y Calomys y a la especie Mus musculus, pero no a Oligoryzomys, el reservorio habitual del genotipo HU39694. Tampoco se detectaron anticuerpos anti-hantavirus en suero de los roedores capturados. La ausencia de registro de viajes a área endémica de este genotipo y los hábitos recreacionales de los pacientes, sumados a los resultados serológicos negativos para hantavirus en los contactos, permiten inferir la posible exposición de los pacientes a fluidos de roedores infectados durante actividades recreativas o sociales al aire libre en sus respectivas áreas de residencia. En conclusión, se demuestra la circulación en Tucumán del genotipo viral HU39694, hasta ahora considerado restringido a la región pampeana central. Se extiende así a Tucumán el área endémica de hantavirosis, pero no se identificó el reservorio en el área.

We describe an outbreak of hantavirus pulmonary syndrome in the Burruyacú Department, Province of Tucumán. The detection in 2016 of a case of hantavirosis affecting a 23-year-old woman, considered at that time to be the first case occurred in that province, promoted a thorough epidemiological study. The investigation allowed the retrospective detection of another case occurred one month earlier in a 5-year-old child in the same Department. In both cases, the infection was confirmed by serology (case 1 at days 4 and 7 of disease onset, case 2 at day 4) and the viral genotype was characterized as HU39694. The contacts of both cases were serologically negative for hantavirus. The rodents captured in the area belonged to genus Akodon, genus Calomys and species Mus musculus. Oligoryzomys, the known reservoir for this viral genotype, was not found. Specific anti-hantavirus antibodies were not detected in the captured rodents. Given that the patients had not visited hantavirus endemic areas and their contacts were negative for hantavirus, we infer that the patients were locally exposed to fluids of infected rodents during their usual social or recreational outdoor activities. In conclusion, we demonstrate that hantavirus HU39694 -a genotype until now considered to be restricted to the Central Pampas of the country- is circulating in the North Western province of Tucumán. The endemic area of hantavirosis is thus expanded to this province but the viral reservoir in the area has not yet been identified.

Fluorescent antibody test, quantitative polymerase chain reaction pattern and clinical aspects of rabies virus strains isolated from main reservoirs in Brazil

ABSTRACTRabies virus (RABV) isolated from different mammals seems to have unique characteristics that influence the outcome of infection. RABV circulates in nature and is maintained by reservoirs that are responsible for the persistence of the disease for almost 4000 years. Considering the different pattern of pathogenicity of RABV strains in naturally and experimentally infected animals, the aim of this study was to analyze the characteristics of RABV variants isolated from the main Brazilian reservoirs, being related to a dog (variant 2),Desmodus rotundus (variant 3), crab eating fox, marmoset, and Myotis spp. Viral replication in brain tissue of experimentally infected mouse was evaluated by two laboratory techniques and the results were compared to clinical evolution from five RABV variants. The presence of the RABV was investigated in brain samples by fluorescent antibody test (FAT) and real time polymerase chain reaction (qRT-PCR) for quantification of rabies virus nucleoprotein gene (N gene). Virus replication is not correlated with clinical signs and evolution. The pattern of FAT is associated with RABV replication levels. Virus isolates from crab eating fox and marmoset had a longer evolution period and higher survival rate suggesting that the evolution period may contribute to the outcome. RABV virus variants had independent characteristics that determine the clinical evolution and survival of the infected mice.

Detección molecular de virus de encefalitis de Saint Louis en mosquitos de Buenos Aires, Argentina

Durante el mes de marzo de 2013 una población de palomas torcazas (Zenaida auriculata) se instaló en una zona céntrica de la ciudad de Buenos Aires. Conociendo el rol que poseen estas aves como hospedadores competentes del virus de la encefalitis de Saint Louis (SLEV), fue colocada en el lugar una trampa de luz tipo CDC, a fin de realizar una vigilancia entomológica. Durante ese mes,fueron capturados 5 grupos de mosquitos (n = 48), 3 correspondieron a la especie Culex pipiens (n = 10) y 2 a Culex spp.(n = 38), no pudiéndose determinar en estos últimos con precisión la especie por encontrarse dañados. En un grupo de mosquitos Culex spp. se detectó el SLEV por técnicas moleculares. Posteriormente fue secuenciado y clasificado como perteneciente al genotipo III.

During March 2013 a population of eared doves (Zenaida auriculata) was established in the center of City of Buenos Aires. Considering the role of these birds as host competent for Saint Louis encephalitis virus (SLEV), a CDC light trap was put in place to perform entomologic surveillance. During this month 5 pools of mosquitoes (n = 48) were collected and taxonomically determined. Three of them were classified as Culex pipiens (n = 10) and the other two were Culex spp. (n = 38). In this case, the mosquitoes species could not be determined due to that individuals were damaged. One of the Culex spp. pool was found to be positive for Saint Louis encephalitis virus by molecular techniques. This was then sequenced and classified as genotype III.

Murciélagos hematófagos como reservorios de la rabia / Hematophagous bats as reservoirs of rabies

La rabia continua siendo un desafío para las autoridades de salud pública y una limitante para la industria ganadera en América Latina. Caninos silvestres y domésticos, así como murciélagos hematófagos son las principales especies transmisoras y reservorios de la enfermedad. Actualmente, se observa variaciones en el perfil epidemiológico de la rabia, donde la especie de murciélago hematófago Desmodus rotundus se constituye en la principal especie transmisora. A lo largo del tiempo se ha acumulado conocimiento sobre la ecología, biología y comportamiento de esta especie y sobre la historia natural de la rabia, lo cual debe conducir a una continua evolución de los métodos de control poblacional de D. rotundus, prevención y técnicas de diagnóstico. Aún se desconoce la relación ecológica de esta especie con otras hematófagas y no hematófagas, y queda mucho por mejorar en los sistemas de notificación y vigilancia epidemiológica, así como crear una mayor conciencia entre los ganaderos ante el tema. La comprensión del impacto que las modificaciones ambientales inducidas por el hombre ejercen sobre la dinámica de infección del virus de la rabia en los murciélagos debe ser motivo de investigaciones posteriores. Esto requerirá la combinación de estudios de campo con modelos matemáticos y nuevas herramientas diagnósticas. La presente revisión pretende presentar los aspectos más relevantes sobre el rol de los murciélagos hematófagos como reservorios y transmisores del virus de la rabia.

Rabies continues to be a challenge for public health authorities and a constraint to the livestock industry in Latin America. Wild and domestic canines and vampire bats are the main transmitter species and reservoirs of the disease. Currently, variations observed in the epidemiological profile of rabies, where the species of hematophagous bat Desmodus rotundus constitutes the main transmitting species. Over the years, knowledge has accumulated about the ecology, biology and behavior of this species and the natural history of rabies, which should lead to continuous development of methods of population control of d. Rotundus as well as prevention and diagnostic tools for rabies. Ecological relationships of this species with other hematophagous and non-hematophagous bats is unknown, and there is much room for improvement in reporting systems and surveillance, as well as creating greater awareness among the farming community. Understanding the impact of human-induced environmental changes on the rabies virus in bats should be cause for further investigation. This will require a combination of field studies with mathematical models and new diagnostic tools. This review aims to present the most relevant issues on the role of hematophagous bats as reservoirs and transmitters of the rabies virus.

Serological survey of hantavirus in rodents in Uberlândia, Minas Gerais, Brazil / Inquérito sorológico de hantavírus em roedores, Uberlândia, Minas Gerais, Brasil

We conducted a serological survey to determine the presence of hantavirus infection in rodents in Uberlândia, Minas Gerais as well as to identify and characterize associated factors. Rodents were captured using Sherman live-capture traps set in rural and peri-urban environments. A total of 611 rodents were captured. There was a higher trap success in peri-urban areas (26.3%) and a higher prevalence of antibodies among rodents captured in rural areas (2.9%). Necromys lasiurus was the most common species (42.2%) and the more frequently infected (4.6%). One Calomys tener (1/141; 0.7%) and one Calomys sp. (1/14; 7.1%) were also positive for the hantavirus infection. In N. lasiurus, antibody prevalence correlated with population density (p < 0.01), age class (p = 0.003) and presence of scars (p = 0.02). The data confirm that horizontal transmission is the main mechanism that maintains the virus in nature. The higher seropositivity in N. lasiurus is consistent with genetic studies that associate this species with an Araraquara virus reservoir; the seropositivity of C. tener and Calomys sp. may indicate the occurrence of spillover infection or the presence of other circulating hantaviruses.

Realizamos um estudo transversal para identificar a presença de infecção por hantavírus em roedores em Uberlândia, Minas Gerais, e também para identificar e caracterizar fatores associados. Roedores foram capturados usando armadilhas do tipo Sherman em ambientes rural e periurbano. Um total de 611 roedores foi capturado. Houve maior sucesso de captura na área periurbana (26,3%) e maior prevalência de anticorpos entre os roedores capturados na área rural (2,9%). Necromys lasiurus foi a espécie mais encontrada (42,2%) e a mais frequentemente infectada (4,6%). Um Calomys tener (1/141; 0.7%) e um Calomys sp. (1/14; 7.1%) foram também positivos. Os dados obtidos mostram que em N. lasiurus, a prevalência de anticorpos está relacionada à densidade populacional (p < 0.01), a classe de idade (p = 0.003) e a presença de cicatrizes (p = 0.02), confirmando que a transmissão horizontal é o principal mecanismo que mantém o vírus na natureza. A maior positividade em N. lasiurus é consistente com estudos genéticos que permitem associar esta espécie como reservatório do vírus Araraquara; a soropositividade de C. tener e Calomys sp. pode indicar a ocorrência de "spillover infection" ou a presença de outros hantavírus circulantes.

Detection of the first incidence of Akodon paranaensis naturally infected with the Jabora virus strain (Hantavirus) in Brazil

We characterised hantaviruses circulating in different Akodon rodent species collected in midwestern Santa Catarina (SC), southern Brazil, where the Jabora hantavirus (JABV) strain was first identified in Akodon montensis. Genetic and phylogenetic analyses based on a partial S segment indicated that, in SC, Akodon paranaensis and A. montensis carried the same type of hantavirus. Additionally, we conducted the first genomic characterisation of the complete S segment from the Brazilian JABV strain. This is the first report of A. paranaensis infected with the JABV.

Características de Oligoryzomys longicaudatus asociadas a la presencia del virus Andes (Hantavirus) / Oligoryzomys longicaudatus characteristics' associated with the presence of Andes virus (Hantavirus)

Oligoryzomys longicaudatus is the main reservoir of Andes virus (AND), which causes hantavirus pulmonary syndrome in Patagonia. The factors associated with the presence of antibodies against AND in this species are unknown. This study used a logistic regression model to analyze which characteristics of O. longicaudatus, captured in northern Argentinean Patagonia, led to an increased probability of an animal having antibodies against AND and to relate these characteristics to possible mechanisms of transmission of the virus within the population. Sex, age, body mass, and wounds were important predictors regarding the presence of antibodies against AND within O. longicaudatus populations. The probability of a wounded male O. longicaudatus adult having AND antibodies increased in parallel with the body mass. The probability of having antibodies was more than 80% in individuals with body masses above 44 gram. However, the possible transmission mechanism of AND within O. longicaudatus population is still uncertain and further studies involving a larger number of individuals and prolonged monitoring including the process of seroconversion are needed.

Oligoryzomys longicaudatus es el principal reservorio del virus Andes Sur (AND) causante del síndrome pulmonar por hantavirus en la Patagonia. Aún se desconoce qué características individuales están asociadas a una mayor presencia de anticuerpos contra AND en esta especie. En este estudio, mediante un modelo de regresión logística evaluamos qué características de O. longicaudatus, capturados en la Patagonia norte de Argentina, incrementan la probabilidad de un individuo de presentar anticuerpos contra AND para relacionarlos con posibles mecanismos de transmisión del virus dentro de la población. El sexo, la edad, la masa corporal y las heridas resultaron factores importantes para la circulación y persistencia del virus dentro de la población de O. longicaudatus. La probabilidad de que un O. longicaudatus, macho, adulto con heridas presente anticuerpos contra AND aumentó con el incremento de la masa corporal, siendo esta probabilidad mayor al 80% en individuos con masas corporales mayores a 44 g. Sin embargo, el posible mecanismo de transmisión de AND dentro de la población de O. longicaudatus queda aún incierto, por lo que son necesarios estudios futuros que involucren un mayor número de individuos y un tiempo prolongado de seguimiento en su proceso de seroconversión.

Uso e ocupação do solo e a disseminação da hantavirose na região de São Sebastião, Distrito Federal: 2004 - 2008 / Land use and occupation and hantavirosis dissemination in the São Sebastião region, Federal District: 2004 - 2008

INTRODUÇÃO: As hantaviroses apresentam distribuição mundial e constituem importante problema de saúde pública. A epidemiologia da hantavirose no Brasil mostra que vem aumentando a cada ano o número de casos que são notificados e de variantes que têm sido descobertas em diversos estados e no Distrito Federal. Neste contexto, o estudo tem como objetivo principal analisar o uso e da ocupação do solo na disseminação da hantavirose no Distrito Federal, no período de 2004 a 2008. MÉTODOS: Para a realização desta pesquisa, foram utilizados dados epidemiológicos e do uso da terra com fins de elaborar tabelas e cartogramas para detalhar a espacialização da hantavirose no território. RESULTADOS: Dos 40 locais prováveis de infecção (LPIs) plotados no Mapa de Cobertura e Uso da Terra, 19 (47 por cento) ocorreram em áreas de pastagens, 10 (25 por cento) em área urbana (periurbana), 6 (15 por cento) em áreas utilizadas para a agricultura e 5 (12 por cento) em espaços de cerrado. CONCLUSÕES: Sendo assim, as atividades agrícolas e a expansão urbana em direção às áreas de cerrado vêm favorecendo a disseminação da hantavirose no Distrito Federal e em especialmente em São Sebastião.

INTRODUCTION: Hantavirosis has worldwide distribution and is an important public health problem. The epidemiology of hantavirosis in Brazil shows that the number of cases notified and the number of variants discovered in several states and the Federal District have been increasing year by year. Within this context, the main objective of this study was to examine land use and occupation in relation to the spread of hantavirosis in the Federal District, between 2004 and 2008. METHODS: To carry out this investigation, epidemiological and land use data were used to drafting tables and cartograms in order to detail the special spread of hantavirosis in this area. RESULTS: Out of the 40 likely infection sites plotted on the coverage and land use map, 19 (47 percent) were in pasture areas, 10 (25 percent) in urban areas (periurban), 6 (15 percent) in areas used for agriculture and 5 (12 percent) in savanna areas. CONCLUSIONS: It can thus be seen that agricultural activities and urban expansion towards the savanna areas have favored the spread of hantavirosis in the Federal District and especially in São Sebastião.

Zoonosis con reservorios silvestres: Amenazas a la salud pública y a la economía: [revisión] / Zoonoses with wildlife reservoirs: A threat to public health and the economy: [review]

The world is experiencing an increase in emergent infections as a result of anthropogenic changes of the biosphere and globalization. Global warming unrestricted exploitation of natural resources such as forests and fisheries, urbanization, human migration, and industrialization of animal husbandry cause environmental destruction and fragmentation. These changes of the biosphere favor local emergence of zoonoses from their natural biotopes and their interaction with domestic animals and human populations. Subsequently, international commerce, human and animal migration and travel, favor the dissemination of these zoonotic pathogens worldwide. Chile is undergoing an important degradation of many wild-life biotopes, affecting their diversity and contributing to the dissemination of zoonoses such as Chagas disease, Hantavirus, rabies, fish tapeworms, and marine vibriosis. Moreover, agents of many other zoonoses such as ¡eptospirosis, hydatidosis, salmonellosis, rabies, brucellosis and anthrax have been detected in different wild-life environments in the country. The intensification and accelerations of the anthropogenic deterioration of the biosphere in Chile, as results of the unrestricted utilization of natural resources and global climate change, suggests that emergence of new zoonoses in the near future will lead to important public health and economic problems. Forestalling of these problems will require active epidemiológica! surveillance of wild and domestic animals with a wide range of modern molecular and ancillary epidemiológica! tools. This also demands government and private sector (i.e., animal husbandry) intervention, funding and the collaboration of professionals in human and veterinary medicine with those in the environmental sciences including ecology, climatology and oceanography.

Characteristics of districts in Pakistan with persistent transmission of wild poliovirus, 2000-2001

We sought to identify factors associated with being a reservoir district for wild poliovirus in Pakistan. Differences between reservoir and non-reservoir districts were identified using acute flaccid paralysis surveillance data, population census statistics and data from a survey of district health officials [DHOs]. Of the 11 poliovirus reservoir districts identified, population density was significantly higher [median 550 persons/km2] than the non-reservoirs [median 175 persons/km2]. DHOs from reservoir districts more often reported that planning was affected by refugees and they had more frequent DHO transfers compared with non-reservoir districts. Multivariate analysis confirmed that reservoirs more often had high population density and frequent DHO transfers. Assessment of district-level and management characteristics can supplement surveillance methods to further improve health programmes

Leptospirose epidêmica em Salvador, Bahia: estudo de reservatórios e desenvolvimento do teste de reação em cadeia da enzima polimerase (pcr) para a sua identificação / Leptospirosis epidemic in Salvador, Bahia: a study of reservoirs and development of the test chain reaction of polymerase enzyme (PCR) for identification

Em Salvador a leptospirose é uma antropozoonose urbana com surtos epidêmicos. A sua letalidade pode chegar a 15%. Em todo o mundo os roedores peridomiciliares são considerados os principais reservatórios sinantrópicos de leptospirose e estão relacionados como aos fatores de risco associados a doença. Em Salvador não existem estudos recentes a respeito dos reservatórios de leptospirose. A partir da importância da doença e da falta de estudos recentes com reservatórios foi desenvolvido esse estudo. Capturar e determinar os reservatórios de leptospirose no município de Salvador. Determinar a prevalência da infecção por leptospiras nesses reservatórios através do teste de microaglutinação (MAT) e isolamento em meio de cultura EMJH (lMC). Caracterizar os sorogrupos de leptospiras nesses reservatórios e comparar com os sorogrupos dos casos humanos. Desenvolver um teste de diagnóstico rápido para leptospirose nos reservatórios através do teste de reação em cadeia da enzima DNA Tac polimerase (PCR). Foram utilizadas armadilhas (Tomahawk live traps, 20X20X60 em, Tomahawk@) para a captura dos animais. Os testes de IMC e MAT foram realizados de acordo com os padrões da OMS. Nos testes de PCR foram utilizados 3 pares de "primers" de Mérien e Gravekamp. Os dados foram analisados em programa de análise de dados epidemiológicos EPI-INFO 6.2 e EXCELL. Foram capturados 142 Rattus norvegicus e 8 Didelphis marsupialis. A positividade dos R. norvegicus ao IMC foi 80%, os D. Marsupialis foram todos negativos. Os R. norvegicus apresentaram 70% de positividade ao teste de MATe os D. Marsupialis 85%. A comparação entre os testes de isolamento em meio de cultura e MAT demonstrou que 89% dos R. norvegicus apresentaram positividade a pelo menos um dos testes. Os testes dos resultados do PCR com o IMC (teste padrão ouro) demostraram, respectivamente, sensibilidade e especificidade de 89% e 97% para o teste de PCR. OS R. norvegicus são o principal reservatório de leptospirose em...