After the first description of TSP/HAM in 1985 and the elaboration of WHO's diagnostic criteria in 1988, the experience of the professionals in this field has increased so that a critical reappraisal of these diagnostic guidelines was considered timely. Brazilian neurologists and observers from other countries met recently to discuss and propose a modified model for diagnosing TSP/HAM with levels of ascertainment as definite, probable, and possible, according to myelopathic symptoms, serological findings, and/or detection of HTLV-I DNA and exclusion of other disorders.

Abstract. Between November 1993 and March 1994, a cluster 6 pediatric patients with acute febrile illnesses associated with rashes was identified in Jujuy Province, Argentina. Immunohistochemical staining of tissues confirmed spotted fever group rickettsial infection in a patient with fatal disease, and testing of serum of a patient convalescing from the illness by using an indirect immunofluorescence assay (IFA) demonstrated antibodies reactive with spotted fever group rickettsiae. A serosurvey was conducted among 16 households in proximity to the index case. Of 105 healthy subjects evaluated by IFA, 19 (18%) Between November 1993 and March 1994, 6 children presented to medical practitioners in Jujuy Province in northwestern Argentina with illnesses characterized by fever, headache, purpuric rash, and a history of tick bite 1-2 weeks preceding the illness. This cluster included two fatal cases occurring in a family residing in Saladillo in the Santa Barbara Department of Jujuy Province (Figure 1). The clinical and epidemiologic findings common to each case suggested a rickettsial etiology. In this report, we describe evidence for spotted fever group rickettsial infections in northern Argentina, including laboratory-confirmed infections in patients with acute disease, and serologic evidence of past rickettsial and ehrlichial infections among healthy persons residing in Jujuy Province. METHODSDescription of the area. Jujuy Province is situated in northwestern Argentina (Figure 1) and is a relatively warm (20-22ЊC) subtropical region located at 2,200 feet (670 meters) elevation. The average annual rainfall is 32 in (80 cm), and most precipitation occurs between December and March. The province has a stable population of approximately 560,000 inhabitants. The study area of Palma Sola and surroundings (which includes the town of Saladillo) has a population of approximately 2,000 persons. It is located in the Department of Santa Barbara, with a population of 15,540 persons. The terrain consists of partially forested rolling hills that support a diverse collection of birds, small, medium, and large mammals, as well as many domesticated animals including dogs, cattle, pigs, and horses. Adult A. cajennense have been collected from dogs and horses in the region.Serosurvey. Healthy persons from 16 households in Saladillo were interviewed and a peripheral blood specimen was collected from each person. The interview included questions on prior tick bites and on illnesses at any time, specifically illnesses with signs and symptoms compatible with rickettsial spotted fever. Informed consent was obtained for the survey following guidelines of the U.S. Department of Health and Human Services and those of the Jujuy Provincial Ministry of Social Welfare for clinical studies.Immunohistochemistry. Sections of formalin-fixed, paraffin-embedded tissues obtained at autopsy from a patient with fatal disease were evaluated for spotted fever group rickettsial infection using an indirect immunoalkaline phosphatase staining technique. 9 ...

BackgroundDiagnosis of primary HIV infection (PHI) has important clinical and public health implications. HAART initiation at this stage remains controversial.MethodsOur objective was to identify predictors of disease progression among Argentinean seroconverters during the first year of infection, within a multicentre registry of PHI-patients diagnosed between 1997 and 2008. Cox regression was used to analyze predictors of progression (LT-CD4 < 350 cells/mm3, B, C events or death) at 12 months among untreated patients.ResultsAmong 134 subjects, 74% presented with acute retroviral syndrome (ARS). Seven opportunistic infections (one death), nine B events, and 10 non-AIDS defining serious events were observed. Among the 92 untreated patients, 24 (26%) progressed at 12 months versus three (7%) in the treated group (p = 0.01). The 12-month progression rate among untreated patients with ARS was 34% (95% CI 22.5-46.3) versus 13% (95% CI 1.1-24.7) in asymptomatic patients (p = 0.04). In univariate analysis, ARS, baseline LT-CD4 < 350 cells/mm3, and baseline and six-month viral load (VL) > 100,000 copies/mL were associated with progression. In multivariate analysis, only ARS and baseline VL > 100,000 copies/mL remained independently associated; HR: 8.44 (95% CI 0.97-73.42) and 9.44 (95% CI 1.38-64.68), respectively.ConclusionsIn Argentina, PHI is associated with significant morbidity. HAART should be considered in PHI patients with ARS and high baseline VL to prevent disease progression.

We describe the first molecular confirmation of Rickettsia rickettsii, the cause of Rocky Mountain spotted fever (RMSF), from a tick vector, Amblyomma cajennense, and from a cluster of fatal spotted fever cases in Argentina. Questing A. cajennense ticks were collected at or near sites of presumed or confirmed cases of spotted fever rickettsiosis in Jujuy Province and evaluated by polymerase chain reaction assays for spotted fever group rickettsiae. DNA of R. rickettsii was amplified from a pool of A. cajennense ticks and from tissues of one of four patients who died during 2003-2004 after illnesses characterized by high fever, severe headache, myalgias, and petechial rash. The diagnosis of spotted fever rickettsiosis was confirmed in the other patients by indirect immunofluorescence antibody and immunohistochemical staining techniques. These findings show the existence of RMSF in Argentina and emphasize the need for clinicians throughout the Americas to consider RMSF in patients with febrile rash illnesses.

The evolutionary rate of the human T-cell lymphotropic virus type-1 (HTLV-1) is considered to be very low, in strong contrast to the related human retrovirus HIV. However, current estimates of the HTLV-1 rate rely on the anthropological calibration of phylogenies using assumed dates of human migration events. To obtain an independent rate estimate, we analyzed two variable regions of the HTLV-1 genome (LTR and env) from eight infected families. Remarkable genetic stability was observed, as only two mutations in LTR (756 bp) and three mutations in env (522 bp) occurred within the 16 vertical transmission chains, including one ambiguous position in each region. The evolutionary rate in HTLV-1 was then calculated using a maximum-likelihood approach that used the highest and lowest possible times of HTLV-1 shared ancestry, given the known transmission histories. The rates for the LTR and env regions were 9.58 x 10(-8)-1.25 x 10(-5) and 7.84 x 10(-7) -2.33 x 10(-5)nucleotide substitutions per site per year, respectively. A more precise estimate was obtained for the combined LTR-env data set, which was 7.06 x 10(-7)-1.38 x 10(-5)substitutions per site per year. We also note an interesting correlation between the occurrence of mutations in HTLV-1 and the age of the individual infected.