Seroprevalencia de HTLV-I/II y factores de riesgo asociados a la infección en la población de donantes de sangre de Córdoba, Argentina / HTLV-I/II seroprevalence and risk factors associated with infection in a blood donor population in Córdoba, Argentina

In this study we have determined the seroprevalence of infections by HTLV-I/II in the blood donor population from the city of Córdoba. A total of 5476 blood donor sera were screened for HTLV-I/II antibodies by particle agglutination assay (PA) (SERODIA HTLV-I, Fujirebio INC, Tokyo, Japan). The reactive sera samples were confirmed by an "in house" indirect immunofluorescence assay (IFA). 14 out of 5476 blood donors studied were PA reactive and were confirmed positive by IFA, showing a prevalence of 0.26 (95 confidence interval: 0.126-0.394). All the positive samples, except one, met the criteria for HTLV-I. Although one HTLV-I infected donor was an intravenous drug abuser and two donors were born in highly endemic areas for HTLV-I, no specific risk factors were identified among the others. The demonstration that HTLV-I circulates in blood donor population of Córdoba, points out that the systematic screening of blood for HTLV-I/II antibodies must be implemented in the blood banks, in an attempt to prevent the spread of infections with this oncogenic virus in Argentina.

Evaluación de los equipos comerciales utilizados en los bancos de sangre de Córdoba para la detección de anticuerpos anti HTLV-I/II / Evaluation of commercial equipment used in blood banks in Córdoba for the detection of anti-HTLV-I/II antibodies

In order to assess the efficiency of currently used screening tests, Abbott HTLV-I/HTLV-II EIA, Vironostika HTLV-I/II Organon Teknika, Particle Agglutination (PA) assay Serodia Fujirebio Inc. (Tokyo, Japan) for HTLV-I/II antibody detection in blood donors samples, a panel of 100 sera from different blood banks of Córdoba city were studied. An "in house" indirect immunofluorescence assay (IFA) was used as reference test. The correlation rates were: 66 for Abbott HTLV-I/HTLV-II EIA, 97 for Vironostika HTLV-I/II Organon Teknika EIA and 99 for PA Serodia. Vironostika HTLV-I/II Organon Teknika EIA and PA Serodia assay proved to be more reliable for HTlV-I/II antibody screening in blood donors from Córdoba, yielding a very low rate of false positive results as compared with Abbot HTLV-I/HTLV-II EIA.

Presencia de anticuerpos contra el virus de la encefalitis equina venezolana subtipo VI en pacientes con enfermedad aguda febril / [Presence of antibodies against Venezuelan equine encephalitis virus subtype VI in patients with acute febrile illness]

In Argentina, there is no record of human cases produced by Dengue virus (Flavivirus), but Paraguay and Brasil (neighbouring countries) have notified human outbreaks of Dengue Haemorrhagic Fever. In this report, we inform the serological results of a limited human outbreak of a Dengue-like acute illness that occurred in General Belgrano Island, Formosa, Argentina in April 1989. This island is 35 km far from Clorinda city of Paraguay river, with a human population of 150 inhabitants. The weather of this area is humid with abundant rainfall, favouring mosquitoes proliferation. Two samples of serum from 28 human notified cases were studied using hemagglutination inhibition test (HI), complement fixation (CF), and plaque reduction neutralization (NT) test in Vero cell cultures. All tested sera were negative to Dengue, St. Louis encephalitis, Yellow Fever, Bussuquara, Rocio, Eastern and Western Equine Encephalitis arboviruses as well as Influenza and Rubella viruses. By contrast, infection with Venezuelan equine encephalitis virus (VEE), subtype VI-AG80-663 strain was demonstrated (34.5

positive by HI, 39.1

by CF and 51.6

by NT). Seroconversion was detected by NT in six cases and only five were positive by CF. The 26.8

of the sera reacted also with VEE subtype I AB by NT. Considering that no cross reaction were detected in NT with these two subtypes, our results suggest that both viruses are concomitantly circulating in the studied area. Furthermore, the seroconversions detected with AG80-663 strain firmly indicate that during the outbreak this virus subtype was circulating in the island, although we could not assure that it was the causal agent of the acute disease.

Actividad concomitante de dos Bunyavirus en caballos de la Argentina / [Concomitant activity of 2 bunyaviruses in horses in Argentina]

A serologic survey of horses for Kairi (KRI) and Cache Valley (CV), two related Bunyaviruses, was conducted simultaneously in Cordoba and Santa Fe provinces, Argentina, during late 1983 and 1984. The prevalence of neutralizing antibodies only for KRI was 13.3

and only for CV was 40.0

; but if the total positive sera for KRI and CV were taken into account, the prevalence reached 48.3 and 75.0

, respectively. The prevalence for CV was higher than for KRI in Cordoba (p less than 0.01), but both were similar in Santa Fe province. The demonstration of seroconversion in horses of the two zones for both viruses indicates that these viruses have a concomitant activity. The infection rates (number of infections per 100 horses-month) were very high in Cordoba (4.4 and 7.1 for KRI and CV) but also in Santa Fe (2.9 and 9.5 for the two viruses respectively), without significant difference in each province. Despite this high activity, no signs of illness or death imputed to these viruses were registered, in these areas during the period of observation. This apparent absence of associated equine disease may be the consequence of the low or null virus pathogenicity or the underrecognition or underreporting of the clinical cases.