RESUMEN
In October 1995, epidemic "hemorrhagic fever," without jaundice or renal manifestations, was reported in rural Nicaragua following heavy flooding; 2259 residents were evaluated for nonmalarial febrile illnesses (cumulative incidence, 6.1%) and 15 (0.7%) died with pulmonary hemorrhage. A case-control study found that case-patients were more likely than controls to have ever walked in creeks (matched odds ratio [MOR], 15.0; 95% confidence interval [CI], 1.7-132.3), have household rodents (MOR, 10.4; 95% CI, 1.1-97.1), or own dogs with titers >/=400 to Leptospira species (MOR, 23.4; 95% CI, 3.6-infinity). Twenty-six of 51 case-patients had serologic or postmortem evidence of acute leptospirosis. Leptospira species were isolated from case-patients and potential animal reservoirs. This leptospirosis epidemic likely resulted from exposure to flood waters contaminated by urine from infected animals, particularly dogs. Leptospirosis should be included in the differential diagnosis for nonmalarial febrile illness, particularly during periods of flooding or when pulmonary hemorrhage occurs.
Asunto(s)
Hemorragia/complicaciones , Leptospirosis/epidemiología , Enfermedades Pulmonares/complicaciones , Adolescente , Adulto , Animales , Estudios de Casos y Controles , Bovinos , Niño , Preescolar , Desastres , Brotes de Enfermedades , Vectores de Enfermedades , Perros , Hemorragia/microbiología , Caballos , Humanos , Incidencia , Lactante , Leptospira/clasificación , Leptospira/aislamiento & purificación , Leptospirosis/complicaciones , Leptospirosis/microbiología , Enfermedades Pulmonares/microbiología , Nicaragua/epidemiología , Roedores , Porcinos , Microbiología del AguaRESUMEN
Neotropical bats were collected from different life zones in Guatemala in 1983 and 1984 to determine the presence and distribution of antibody against 10 viruses. Bats were collected with mist nets at 13 sites in eight departments and 332 serum specimens were obtained for testing for neutralizing (N) antibody by the plaque-reduction neutralization test. Eighty-seven (26%) of the 332 bats from 16 (38%) of 42 bat species sampled were serologically positive for five of six arboviruses and for two other viruses tested. Antibodies against Venezuelan equine encephalitis (VEE) variant I-A/B, eastern equine encephalitis, western equine encephalitis, St. Louis encephalitis, vesicular stomatitis, Tacaribe, and Rio Bravo viruses were detected in resident species of bats. However, N antibodies against the enzootic strain of VEE (Mena II, variant I-E) or Nepuyo viruses were not detected.
Asunto(s)
Anticuerpos Antivirales/sangre , Quirópteros , Reservorios de Enfermedades , Virosis/veterinaria , Animales , Infecciones por Arbovirus/epidemiología , Infecciones por Arbovirus/veterinaria , Arbovirus/inmunología , Guatemala/epidemiología , Pruebas de Neutralización/veterinaria , Prevalencia , Estudios Seroepidemiológicos , Virosis/epidemiologíaRESUMEN
During 1988 and 1989, a serologic survey of wildlife was conducted in northeastern Mexico to determine the presence, prevalence, and distribution of arboviruses and other selected disease agents. Eighty mammal specimens were tested. Antibodies to vesicular stomatitis-Indiana, Venezuelan equine encephalitis-Mena II, Rio Grande virus, and vesicular stomatitis-New Jersey were detected predominantly in small mammals. Deer and mouflon (Ovis musimon) had antibodies to bluetongue and epizootic hemorrhagic disease. Two species had serologic evidence of recent exposure to Francisella tularensis. A white-tailed deer (Odocoileus virginianus) had antibodies to Anaplasma marginale. All specimens tested for antibodies against Yersinia pestis and Brucella abortus were negative. Sera from 315 birds were tested for antibody against five equine encephalitis viruses and six avian pathogens. During 1988, antibodies to Venezuelan equine encephalitis-Mena II, Venezuelan equine encephalitis-TC83, St. Louis encephalitis, eastern equine encephalitis, and western equine encephalitis were detected in birds of several species. Antibodies to Pasteurella multocida and Newcastle disease virus were also detected. Birds from five species presented antibodies to Mycoplasma meleagridis. Specimens tested for M. gallisepticum, M. synoviae, and Chlamydia psittaci were negative. To the best of our knowledge, this survey represents the first serologic evidence of bluetongue, Cache Valley virus, epizootic hemorrhagic disease, Jamestown Canyon virus, vesicular stomatitis-Indiana, vesicular stomatitis-New Jersey, Rio Grande virus, and tularemia reported among wildlife in Mexico.
Asunto(s)
Animales Salvajes , Infecciones por Arbovirus/veterinaria , Enfermedades de las Aves/epidemiología , Infecciones/veterinaria , Mamíferos , Animales , Anticuerpos Antibacterianos/sangre , Anticuerpos Antivirales/sangre , Infecciones por Arbovirus/epidemiología , Arbovirus/inmunología , Infecciones Bacterianas/epidemiología , Infecciones Bacterianas/veterinaria , Aves , Infecciones/epidemiología , México/epidemiología , Prevalencia , Virosis/epidemiología , Virosis/veterinariaRESUMEN
Cloacal swabs from 110 adult black-bellied whistling ducks trapped at Laguna La Nacha, Tamaulipas, Mexico, were cultured to determine the prevalence of normal and potentially pathogenic bacteria. Twenty-five gram-negative enterobacteria and four gram-positive cocci were isolated. The most common isolates included Escherichia coli (54%), Staphylococcus spp. (29%), Streptococcus spp. (22%), Aeromonas hydrophila (15%) Enterobacter cloacae (14%), and Micrococcus sp. (14%). The implications of whistling ducks as possible reservoirs of pathogenic bacteria are discussed.
Asunto(s)
Bacterias/aislamiento & purificación , Infecciones Bacterianas/veterinaria , Enfermedades de las Aves/microbiología , Cloaca/microbiología , Patos/microbiología , Animales , Bacterias/patogenicidad , Infecciones Bacterianas/microbiología , Portador Sano/microbiología , Portador Sano/veterinaria , Reservorios de Enfermedades , Enterobacteriaceae/aislamiento & purificación , Enterobacteriaceae/patogenicidad , Infecciones por Enterobacteriaceae/microbiología , Infecciones por Enterobacteriaceae/veterinaria , MéxicoRESUMEN
To assess a possible role of ticks as the maintenance host for epizootic strains of Venezuelan equine encephalomyelitis (VEE) virus, laboratory experiments were conducted to determine if ticks could become infected, maintain, and transmit the virus. Larval and nymphal Amblyomma cajennense (F.) and larval Dermacentor nitens Neumann ticks were exposed to epizootic VEE virus (Trinidad donkey strain) by allowing them to feed on viremic guinea pigs (strain 13). In A. cajennense, transstadial transmission was observed from larvae to nymphs and adults. Horizontal viral transmission to a mammalian host was accomplished by nymphs. Infection rates in nymphs and adults were 2% (42/2,750) and 4% (9/244), respectively, afer ingestion of virus as larvae. Virus was detected in A. cajennense adult ticks for up to 171 d after infection in the larval stage. A cajennense, exposed as nymphs, ingested virus but did not become infected (0/164 after 10 d after taking an infective bloodmeal). No virus was detected in D. nitens 7 d after exposure. These findings suggest that A. cajennense potentially could be involved in an interepizootic maintenance cycle of epizootic VEE viral strains.
Asunto(s)
Vectores Arácnidos/microbiología , Virus de la Encefalitis Equina Venezolana/aislamiento & purificación , Encefalomielitis Equina Venezolana/transmisión , Garrapatas/microbiología , Animales , Cobayas , Larva/microbiologíaRESUMEN
Five new phlebotomus fever virus serotypes (Bunyaviridae: Phlebovirus) are described. These viruses, designated Ambe, Ixcanal, Mariquita, Armero, and Durania, were isolated from sand flies (Diptera: Psychodidae) collected in Brazil, Colombia, and Guatemala. Two of the agents were recovered from pools of male sand flies. The new viruses are antigenically related to other members of the phlebotomus fever serogroup by immunofluorescence, but are distinct from the other 39 members of this serogroup by plaque reduction neutralization test.
Asunto(s)
Bunyaviridae/clasificación , Phlebovirus/clasificación , Psychodidae/microbiología , Animales , Animales Recién Nacidos , Antígenos Virales/análisis , Brasil , Colombia , Femenino , Técnica del Anticuerpo Fluorescente , Guatemala , Humanos , Masculino , Ratones , Pruebas de Neutralización , Phlebovirus/inmunología , Serotipificación , Clima Tropical , Células VeroRESUMEN
Vertebrate animals collected in Haiti in 1972 were tested for selected zoonotic diseases. No rabies virus or neutralizing (N) antibody was detected in bats (Artibeus jamaicensis). However, N antibody against St. Louis encephalitis, Western equine encephalitis (WEE), and Eastern equine encephalitis were detected in resident species of birds and WEE antibody in bats. No N antibody against Venezuelan equine encephalitis was found. The possible introduction by migratory birds and local transmission of these arboviruses is discussed.
Asunto(s)
Zoonosis/epidemiología , Animales , Enfermedades de las Aves/epidemiología , Aves , Quirópteros , Virus de la Encefalitis Equina del Este , Virus de la Encefalitis Equina del Oeste , Encefalitis de San Luis/epidemiología , Encefalitis de San Luis/veterinaria , Encefalomielitis Equina/epidemiología , Encefalomielitis Equina/veterinaria , Haití , Rabia/epidemiología , Rabia/veterinariaRESUMEN
Sixty-three birds representing 13 species were inoculated with a strain of epidemic Venezuelan encephalitis (VE) virus from the 1971 Texas outbreak. More than 95% of the birds became infected. Mortality which could be attributed to infection with VE virus was very low. Viremia persisted 2-6 days. Peak viremia levels ranged from 10(3.2) to 10(8.2) suckling mouse intracranial 50% lethal doses per milliliter (SMICLD50/ml). Blood virus levels were highest in juvenile Louisiana Herones, adult Robins and adult Mockingbirds and were lowest in juvenile Common Egrets. Most bird species had blood virus levels about 10(5) SMICLD50/ml (high vector infection potential) for 2-3 days. Neutralizing antibody response was more uniform and frequent in herons (95%) than in passerines (56%). The role of birds in the epidemiology of Venezuelan is discussed.
Asunto(s)
Enfermedades de las Aves/transmisión , Encefalitis por Arbovirus/veterinaria , Encefalomielitis Equina/veterinaria , Encefalomielitis Equina Venezolana/veterinaria , Aedes , Animales , Anticuerpos Antivirales/análisis , Aves , Vectores de Enfermedades , Encefalitis por Arbovirus/inmunología , Encefalitis por Arbovirus/transmisión , Encefalomielitis Equina Venezolana/inmunología , Encefalomielitis Equina Venezolana/transmisión , Insectos VectoresRESUMEN
The effects of aerial ultralow volume (ULV) malathion on selected species of nontarget animals in Haiti are reported. Mortality of certain groups of insects such as bees, flies, beetles, and butterflies was observed immediately following spray application. Minor fish mortality occurred only in shallow water exposed to direct spray. The brain acetylcholine esterase levels of living fish, tree lizards, birds and bats collected from treated areas were not significantly reduced. No ill or dead animals, besides the few fish, were seen even when maximum exposure occurred. Only minor changes in the feeding behavior of some insectivorous birds were observed. The relative bird density decreased substantially for only one species during the study, and other factors besides treatment were considered to be the reasons for the decline. Aerial applications of ULV malathion at dosages sufficient to dramatically reduce anopheline populations did not significantly affect nontarget vertebrates in this tropical environment.
Asunto(s)
Ecología , Malaria/prevención & control , Malatión/toxicidad , Control de Mosquitos/métodos , Plasmodium falciparum , Acetilcolinesterasa/metabolismo , Aeronaves , Animales , Anopheles , Aves , Encéfalo/enzimología , Quirópteros , Brotes de Enfermedades/epidemiología , Brotes de Enfermedades/prevención & control , Exposición a Riesgos Ambientales , Estudios de Evaluación como Asunto , Peces , Haití , Humanos , Insectos/efectos de los fármacos , Lagartos , Malaria/epidemiología , Malatión/administración & dosificación , Densidad de Población , Estudios ProspectivosRESUMEN
Epidemic Venezuelan equine encephalitis in North America in 1971: vertebrate field studies. Am J Epidemiol 101:36-50, 1975.-In June 1971, epidemic Venezuelan equine encephalitis (VEE) invaded the lower Rio Grande Valley in south Texas. The Boca Chica area of Cameron County was selected as a study site to investigate vertebrate involvement in the natural cycle of epidemic VEE on the basis of considerable evidence of VEE virus activity there in equines, humans, and mosquito vectors. Only one VEE virus isolation was made from 4739 wild and domestic non-equine vertebrates, although numerous equine and human VEE virus isolations were made in concurrent studies. Serologic studies indicated that VEE virus activity was far greater in large domestic animals than in wild birds, wild mammals, or reptiles. Apparently epidemic VEE virus failed to establish itself in a wild vertebrate cycle in south Texas, since VEE antibody was found only in rabbits in 1972. Eventual cessation of VEE transmission in south Texas has been attributed 1) to the elimination of equines as a source of VEE virus by death, naturally acquired antibodies, or vaccination, 2) to quarantines, 3) to mosquito control, and 4) to the failure of epidemic VEE virus to become established in the wild vertebrate population. Equines emerge as the most important vertebrate host in the amplification and spread of virus during an epidemic of VEE.