An outbreak of acute bartonellosis (Oroya fever) in the Urubamba region of Peru, 1998.

During May 1998, we conducted a case-control study of 357 participants from 60 households during an outbreak of acute bartonellosis in the Urubamba Valley, Peru, a region not previously considered endemic for this disease. Blood and insect specimens were collected and environmental assessments were done. Case-patients (n = 22) were defined by fever, anemia, and intra-erythrocytic coccobacilli seen in thin smears. Most case-patients were children (median age = 6.5 years). Case-patients more frequently reported sand fly bites than individuals of neighboring households (odds ratio [OR] = 5.8, 95% confidence interval [CI] = 1.2-39.2), or members from randomly selected households > or = 5 km away (OR = 8.5, 95% CI = 1.7-57.9). Bartonella bacilliformis isolated from blood was confirmed by nucleotide sequencing (citrate synthase [g/tA], 338 basepairs). Using bacterial isolation (n = 141) as the standard, sensitivity, specificity, and positive predictive value of thin smears were 36%, 96%, and 44%, respectively. Patients with clinical syndromes compatible with bartonellosis should be treated with appropriate antibiotics regardless of thin-smear results.

Importancia de la Lutzomia peruensis en la transmisión de la enfermedad de Carrión en el Valle Sagrado de los incas. Urubamba Cusco, Perú / Importance of Lutzomyia peruensis in the transmission of the Carrionïs disease in the Incaïs Sacred Valley. Urubamba Cusco, Peru

En el valle Sagrado de los Incas (Valle del Río Urubamba) encontramos una sola de Lutzomyia, nos referimos a la Lutzomyia suele compartir su habitat con el vector de la enfermedad de Carrión, la Lutzomyia verrucarum. Los aspectos entomológicos fueron levados a cabo, en Mayo de 1998. Las colectas entomológicas se realizaron utilizando trampas de luz CDC toda la noche y en capturas diurnas en las viviendas.Se muestra la importancia de Lutzomyia peruensis incriminándola epidemiológicamente y se detectó Bartonella bacilliformis mediante PCR y haciendo secuenciamiento de ADN. Se presenta también la estimación del riesgo entomólogico de transmisión de bartonelosis por Lutzomyia peruensis, mediante el índice de inoculación de Bartonella bacilliformis

An outbreak of hantavirus pulmonary syndrome, Chile, 1997.

An outbreak of 25 cases of Andes virus-associated hantavirus pulmonary syndrome (HPS) was recognized in southern Chile from July 1997 through January 1998. In addition to the HPS patients, three persons with mild hantaviral disease and one person with asymptomatic acute infection were identified. Epidemiologic studies suggested person-to-person transmission in two of three family clusters. Ecologic studies showed very high densities of several species of sigmodontine rodents in the area.

Venezuelan hemorrhagic fever: clinical and epidemiological studies of 165 cases.

Epidemiological and clinical data are presented on 165 cases of Venezuelan hemorrhagic fever (VHF), a newly emerging viral zoonosis caused by Guanarito virus (of the family Arenaviridae). The disease is endemic in a relatively circumscribed area of central Venezuela. Since its first recognition in 1989, the incidence of VHF has peaked each year between November and January, during the period of major agricultural activity in the region of endemicity. The majority of cases have involved male agricultural workers. Principal symptoms among the patients with VHF included fever, malaise, headache, arthralgia, sore throat, vomiting, abdominal pain, diarrhea, convulsions, and a variety of hemorrhagic manifestations. The majority of patients also had leukopenia and thrombocytopenia. The overall fatality rate among the 165 cases was 33.3%, despite hospitalization and vigorous supportive care.

Prevalence of infection with Junin virus in rodent populations in the epidemic area of Argentine hemorrhagic fever.

We report the results of indirect fluorescent antibody screening for antibody to Junin virus in 1,101 sera from small mammals captured on two mark-recapture grids in the epidemic area of Argentine hemorrhagic fever. Twenty-six of 29 seropositive animals were the cricetid rodent Calomys musculinus, for a 30-month prevalence of 7.9% in that species. Combining these data with previously published data on antigen detection provided an estimated total prevalence of infection of 10.9% for this, the principal reservoir species. Other infected species included two cricetids, C. laucha and Bolomys obscurus, and a predatory carnivore, Galictis cuja. Approximately half of infected animals simultaneously carried serum antibody and antigen in blood and saliva, some for 29-61 days. Except for C. laucha, which was associated with crop habitats, seropositive animals were strongly associated with the relatively rare roadside and fence-line habitats. Seropositive C. musculinus were predominantly males in the oldest age and heaviest body mass classes, and seropositive males were twice as likely to have body scars as seronegative males. These observations suggest that most infections were acquired through horizontal transmission and that aggressive encounters among adult, male C. musculinus in relatively densely populated roadside and fence-line habitats are an important mechanism of transmission of Junin virus within reservoir populations.

A longitudinal study of Junin virus activity in the rodent reservoir of Argentine hemorrhagic fever.

We monitored Junin virus (JV) activity in rodent populations for 30 months at seven mark-recapture grids located in agricultural fields and adjacent roadsides and fence lines in endemic and nonendemic areas of Argentine hemorrhagic fever. Blood and oral swabs taken from rodents captured at five-week intervals were analyzed by enzyme-linked immunosorbent assay for JV antigen (Ag). Calomys laucha and C. musculinus were the most frequently captured rodents, making up 47% and 22% of captures, respectively. Of 41 Ag-positive captures, 37 were C. musculinus and four were C. laucha; 34 were from two trapping grids in the same locality. Antigen-positive Calomys were more frequently male (76%), and were found significantly more frequently among the oldest animals and the largest body mass classes. These patterns, combined with the greater mobility and higher frequencies of wounds among males than females, implicated horizontal transmission as the primary route of JV transmission between rodents. Seasonal maximum levels in JV prevalence (up to 25% of captured Ag-positive C. musculinus) occurred during periods of maximal population densities of Calomys. Spatial distribution of Ag-positive rodents reflected habitat preferences; most Ag-positive C. musculinus were captured from border habitats (roadsides and fence lines), and all Ag-positive C. laucha were captured in crop fields. These distinct, but previously undocumented, habitat preferences suggest that the disease in humans may be related to exposures to the primary reservoir species, C. musculinus, in border habitats rather than in crop fields.

Junin virus activity in rodents from endemic and nonendemic loci in central Argentina.

Small mammals were trapped during a 21-month period at 27 farm sites in 15 localities within and beyond the known endemic area for Argentine hemorrhagic fever (AHF). Prevalence of Junin virus (JV) was assessed by antigen-capture enzyme immunoassay (ELISA) on samples of body fluids and/or organs from 3, 282 captured rodents. Infection in rodent populations was variable (0-3.7%) among localities but, in all cases, was lower than previously reported rates. Overall prevalence was 1.4% in the AHF epidemic area, 0.6% in the historic (currently low incidence of AHF) area, and 0.4% in two localities beyond the previously defined endemic area. These low values underestimate the actual prevalence of JV, as ELISA validation by virus isolation indicated a sensitivity of 30% and a specificity of 99%. Of 37 positive rodents, 28 (76%) were of two species: Calomys musculinus (23 animals) and C. laucha (5 animals). Antigen also was found in three Akodon azarae, four Bolomys obscurus, one Mus musculus, and one Oxymycterus rufus, and JV was isolated from two Oligoryzomys flavescens. Three of these rodent species (B. obscurus, O. flavescens, and O. rufus) have heretofore not been implicated in JV maintenance in the field. Evidence suggests that the AHF endemic area may continue to expand northward.

[New findings on Junin virus infection in rodents inside and outside the endemic area of hemorrhagic fever in Argentina]. / Nuevas observaciones de la infección de roedores por el virus Junin dentro y fuera de la zona endemica de la Fiebre Hemorragica Argentina.

In conjunction with field trials for a vaccine against Argentine Hemorrhagic Fever (AHF), small mammals were trapped during a 28-month period (1 November 1987 to 13 March 1990) in 3 epidemiologically defined areas of the central Argentine pampas: northern and central Buenos Aires provinces were included in the AHF "historic" area, where the disease was common 15-20 years ago, but case rates are currently low; southern Santa Fe province is the current high-incidence area for AHF; the nonendemic area was represented by two localities 60-90 km beyond the northernmost extension of human disease. Animals were live-trapped for 3 days per month in permanent "mark-recapture" grids in each of the 3 areas. Samples of blood, sera, and oral swabs were taken from these animals before they were marked and released at the site of capture. In addition, "removal" traplines provided animals from 16 localities in these 3 areas which were sacrificed to obtain samples of organs in addition to the aforementioned samples. Samples were tested for the presence of Junin virus (JV) antigen by enzyme immunoassay (ELISA). In this assay, a pool of 13 mouse anti-JV glycoprotein and nucleocapsid monoclonal antibodies adsorbed to the surface of microtiter plates was used to capture JV antigen in sample suspensions. A polyclonal rabbit anti-JV antiserum was added as a detector antibody, and an anti-rabbit antibody conjugated to horseradish peroxidase applied with substrate to complete the sandwich.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuevas observaciones de la infección de roedores por el virus Junin dentro y fuera de la zona endemica de la Fiebre Hemorragica Argentina. / [New findings on Junin virus infection in rodents inside and outside the endemic area of hemorrhagic fever in Argentina]

In conjunction with field trials for a vaccine against Argentine Hemorrhagic Fever (AHF), small mammals were trapped during a 28-month period (1 November 1987 to 13 March 1990) in 3 epidemiologically defined areas of the central Argentine pampas: northern and central Buenos Aires provinces were included in the AHF [quot ]historic[quot ] area, where the disease was common 15-20 years ago, but case rates are currently low; southern Santa Fe province is the current high-incidence area for AHF; the nonendemic area was represented by two localities 60-90 km beyond the northernmost extension of human disease. Animals were live-trapped for 3 days per month in permanent [quot ]mark-recapture[quot ] grids in each of the 3 areas. Samples of blood, sera, and oral swabs were taken from these animals before they were marked and released at the site of capture. In addition, [quot ]removal[quot ] traplines provided animals from 16 localities in these 3 areas which were sacrificed to obtain samples of organs in addition to the aforementioned samples. Samples were tested for the presence of Junin virus (JV) antigen by enzyme immunoassay (ELISA). In this assay, a pool of 13 mouse anti-JV glycoprotein and nucleocapsid monoclonal antibodies adsorbed to the surface of microtiter plates was used to capture JV antigen in sample suspensions. A polyclonal rabbit anti-JV antiserum was added as a detector antibody, and an anti-rabbit antibody conjugated to horseradish peroxidase applied with substrate to complete the sandwich.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuevas observaciones de la infección de roedores por el virus Junin dentro y fuera de la zona endemica de la Fiebre Hemorragica Argentina. / [New findings on Junin virus infection in rodents inside and outside the endemic area of hemorrhagic fever in Argentina]

In conjunction with field trials for a vaccine against Argentine Hemorrhagic Fever (AHF), small mammals were trapped during a 28-month period (1 November 1987 to 13 March 1990) in 3 epidemiologically defined areas of the central Argentine pampas: northern and central Buenos Aires provinces were included in the AHF [quot ]historic[quot ] area, where the disease was common 15-20 years ago, but case rates are currently low; southern Santa Fe province is the current high-incidence area for AHF; the nonendemic area was represented by two localities 60-90 km beyond the northernmost extension of human disease. Animals were live-trapped for 3 days per month in permanent [quot ]mark-recapture[quot ] grids in each of the 3 areas. Samples of blood, sera, and oral swabs were taken from these animals before they were marked and released at the site of capture. In addition, [quot ]removal[quot ] traplines provided animals from 16 localities in these 3 areas which were sacrificed to obtain samples of organs in addition to the aforementioned samples. Samples were tested for the presence of Junin virus (JV) antigen by enzyme immunoassay (ELISA). In this assay, a pool of 13 mouse anti-JV glycoprotein and nucleocapsid monoclonal antibodies adsorbed to the surface of microtiter plates was used to capture JV antigen in sample suspensions. A polyclonal rabbit anti-JV antiserum was added as a detector antibody, and an anti-rabbit antibody conjugated to horseradish peroxidase applied with substrate to complete the sandwich.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuevas observaciones de la infección de roedores por el virus Junin dentro y fuera de la zona endemica de la Fiebre Hemorragica Argentina / [New findings on Junin virus infection in rodents inside and outside the endemic area of hemorrhagic fever in Argentina]

In conjunction with field trials for a vaccine against Argentine Hemorrhagic Fever (AHF), small mammals were trapped during a 28-month period (1 November 1987 to 13 March 1990) in 3 epidemiologically defined areas of the central Argentine pampas: northern and central Buenos Aires provinces were included in the AHF [quot ]historic[quot ] area, where the disease was common 15-20 years ago, but case rates are currently low; southern Santa Fe province is the current high-incidence area for AHF; the nonendemic area was represented by two localities 60-90 km beyond the northernmost extension of human disease. Animals were live-trapped for 3 days per month in permanent [quot ]mark-recapture[quot ] grids in each of the 3 areas. Samples of blood, sera, and oral swabs were taken from these animals before they were marked and released at the site of capture. In addition, [quot ]removal[quot ] traplines provided animals from 16 localities in these 3 areas which were sacrificed to obtain samples of organs in addition to the aforementioned samples. Samples were tested for the presence of Junin virus (JV) antigen by enzyme immunoassay (ELISA). In this assay, a pool of 13 mouse anti-JV glycoprotein and nucleocapsid monoclonal antibodies adsorbed to the surface of microtiter plates was used to capture JV antigen in sample suspensions. A polyclonal rabbit anti-JV antiserum was added as a detector antibody, and an anti-rabbit antibody conjugated to horseradish peroxidase applied with substrate to complete the sandwich.(ABSTRACT TRUNCATED AT 250 WORDS)