Seroprevalence of and risk factors for HIV-1 infection among female commercial sex workers in South America

OBJECTIVE

Assessment of HIV prevalence and associated risk behaviours among female commercial sex workers (FCSW) across major cities in South America.

METHODS

Seroepidemiological, cross sectional studies of 13 600 FCSW were conducted in nine countries of South America during the years 1999-2002. Participants were recruited in brothels, massage parlours, hotels, and streets where anonymous questionnaires and blood samples were collected. HIV infection was determined by enzyme linked immunosorbent assay (ELISA) screening and western blot confirmatory tests.

RESULTS

The overall HIV seroprevalence was 1.2% (range 0.0%-4.5%). The highest HIV seroprevalences were reported in Argentina (4.5%) and Paraguay (2.6%); no HIV infected FCSW were detected in Venezuela and Chile. Consistent predictors of HIV seropositivity were: (1) a previous history of sexually transmitted infections (STI, AORs = 3.8-8.3), and (2) 10 years or more in commercial sex work (AORs = 2.2-24.8). In addition, multiple (> or =3) sexual contacts (AOR = 5.0), sex with foreigners (AOR = 6.9), use of illegal drugs (AOR = 3.2), and marijuana use (AOR = 8.2) were associated with HIV seropositivity in Southern Cone countries.

CONCLUSIONS

Consistently low HIV seroprevalences were detected among FCSW in South America, particularly in the Andean region. Predictors of HIV infection across the continent were STI and length of commercial sex work; however, use of illegal drugs, especially marijuana, and sexual contacts with foreigners were also found to be associated risk factors in the Southern Cone region. Interventions for the control of HIV and other STI need to be region and country specific; drug use appears to have an ever increasing role in the spread of HIV among heterosexually active populations.

Documentation of subtype C HIV Type 1 strains in Argentina, Paraguay, and Uruguay

HIV subtypes B, F, and BF recombinants have been previously reported in South America. This report describes the presence of HIV-1 subtype C infection in the countries of Argentina, Uruguay, and Paraguay dating back to at least 1999. Surveillance for uncommon non-B/non-F subtype viruses circulating in South America has been conducted in samples obtained from nine countries. Peripheral blood mononuclear cells (PBMC), dried filter paper (FP), and fresh blood (FB) samples were collected from HIV-positive patients from Ecuador, Colombia, Venezuela, Peru, Chile, Bolivia, Argentina, Uruguay, and Paraguay. From a total of 2962 HIV seropositive samples examined during a 9-year period (1995-2003), only 11 (0.4%) were found to be infected with non-B/non-F HIV variants. Eight of these 11 strains were determined to be subtype C by heteroduplex mobility assay (HMA). Five of these 8 strains were further characterized by sequencing and phylogenetic analysis of the protease (Pro) and reverse transcriptase (RT) region of the genome and two were sequenced full length. One of the strains was found to be a unique BC recombinant. The spread of a third subtype of HIV, subtype C, should raise the question of its potential future role in the HIV epidemic in this region.

Underestimation of Mycobacterium tuberculosis infection in HIV-infected subjects using reactivity to tuberculin and anergy panel

BACKGROUND

This study aimed to evaluate purified protein derivative (PPD) reactivity and its interrelationship with anergy panel and CD4+ lymphocytes in HIV-infected subjects as compared to PPD reactivity in HIV-uninfected individuals in a tuberculosis endemic and high Bacillus Calmette-Guérin (BCG) coverage environment.

METHODS

Clients of four Mexico City HIV detection centres were screened for HIV-1 antibodies (ELISA or haemagglutination, Western Blot); reactivity to PPD (Mantoux PPD, 5TU RT-23), Candida (1:1000, 0.1 ml), and tetanus toxoid (10Lf, 0.1 ml); and CD4+ T cells. Active tuberculosis was excluded. Informed consent was obtained.

RESULTS

From 5130 clients 1168 subjects were enrolled; of these 801 (68.6%) were HIV positive. Reactivity to PPD among HIV-positive subjects was found in 174 (22%), 261 (32.6%), and 296 (37%), at PPD cutoff levels of > or =10 mm, > or =5 mm, and > or =2 mm as compared to 224 (61%) of 367 HIV-negative individuals' reactors to PPD (> or =10 mm) (P < 0.001). After exclusion of anergic individuals using two cutoff levels for cutaneous allergens (< or =2 mm and < or =5 mm), PPD reactivity between HIV-infected and uninfected individuals continued to be significantly different. Only HIV-infected individuals with CD4+ T cells > or =500 cells/mm3 had similar reactivity to PPD as HIV-uninfected individuals. Variables associated with PPD reactivity were CD4+ T cell counts, BCG scar, HIV infection and age.

CONCLUSIONS

PPD reactivity was useful to diagnose tuberculosis infection only among HIV-infected individuals with CD4+ counts > or =500 cells/mm3. Among individuals with lower counts, lowering cutoff levels or using anergy panel did not permit comparable reactivity as that observed among HIV-uninfected individuals.

Opportunistic infections in pediatric HIV infection: a study of 74 autopsy cases from Latin America. The Latin American AIDS Pathology Study Group

The present report describes opportunistic infections found at 74 autopsies of pediatric HIV/AIDS patients performed at several hospitals in Latin American countries. Fungal infections were the most common (53 cases), Candida sp. (39.18%) and Pneumocystis carinii (20.27%) being the most frequently recognized. Other fungal diseases included histoplasmosis, aspergillosis, and cryptococcosis. Viral infections were present in 31 cases, 38.7% being due to cytomegalovirus. Other viruses recognized included herpes simplex and adenovirus. Additional opportunistic infections were due to Mycobacterium avium-intracellulare, toxoplasmosis, and tuberculosis. Nonspecific bacterial bronchopneumonia was present in 11 cases. Cytomegalovirus and P. carinii coinfection was the most common association found. In this series patients died at a younger age (72% at or younger than 1 year old) and there was a slightly higher number of cases of histoplasmosis and brain toxoplasmosis than in other previously published series of infants and children.

HIV/AIDS and its interaction with tuberculosis in Latin America and the Caribbean

At present, human immunodeficiency virus (HIV) is thought to have infected over 17 million people worldwide, over 1 million in North America and roughly 2 million in Latin America and the Caribbean. By comparison, infection with the tuberculosis (TB) agent Mycobacterium tuberculosis is far more common, current estimates indicating that roughly one-third of the world's population is infected. These two infections tend to aggravate each other. That is, HIV leads to a progressive immune system depression that favors reactivation of TB in people with latent tuberculous infections; it promotes progression of TB primary infections or reinfections to full-blown tuberculous disease; and it fosters TB transmission, because those simultaneously infected with HIV and M. tuberculosis tend to develop a bacilliferous and contagious TB that can be transmitted to other susceptible individuals, even though the latter are HIV-negative. In addition, this coinfection tends to promote circulation of drug-resistant M. tuberculosis and to produce peculiar manifestations that complicate TB diagnosis, treatment, and control. Overall, it seems clear that the growing threat posed by these associated agents demands effective action in the form of well-coordinated measures involving throughgoing participation by all countries.

Acute lower respiratory infection in Argentinian children: a 40 month clinical and epidemiological study

In a total of 1,003 children (805 inpatients and 198 outpatients) with acute lower respiratory infections (ALRI), clinical, social, and environmental data were analyzed. The major clinical entities were bronchiolitis, pneumonia, bronchitis, and laryngitis. The first two of these predominated in inpatients; pneumonia and bronchitis were more common in older children, while bronchiolitis was observed in infants. Respiratory rates of > 50/min. were more common in younger children and in cases with bronchiolitis and bronchitis. Retractions showed markedly less age-dependent variations and were present in all severe cases with different clinical diagnoses. Retractions alone or associated with cyanosis were the best indicators for severity of ALRI. Among outpatients, fever and wheezing were more common; inpatients were younger, more frequently malnourished, and from a lower socioeconomic level; family history of chronic bronchitis, crowding, and parental smoking also prevailed in this group. Family asthma and exposure to domestic aerosols was more common among outpatients. Prematurity rate (17 and 15%) of all ALRI cases was twice that of the general pediatric population and a significant difference existed between in- and outpatients under 6 months of age when perinatal respiratory pathologies predominated among inpatients. It is suggested to consider the need for assessing personal, family, and environmental risk factors in addition to clinical signs and symptoms when severe cases of ALRI are evaluated.

Role of drug injection in the spread of HIV in Argentina and Brazil

Drug injectors' have become the second largest HIV transmission category in Argentina and Brazil, as is the case in many pattern I countries, making up more than one-quarter of all AIDS cases reported by 1991. HIV seroprevalence data suggest that the expanding proportion of AIDS cases attributable to drug injection stems from an absolute increase in the number of AIDS cases among drug injectors, and is not merely reflective of a decline in the proportion of cases reported in other transmission categories. Results of a review of studies in Argentina and Brazil indicate that HIV seroprevalence is increasing rapidly, contrary to the situation in some pattern I countries in which HIV seroprevalence among drug injectors is either stably high or increasing only slightly. Also contrary to most pattern I countries, cocaine rather than heroin is the injected drug of choice in Argentina and Brazil. Given that injectors of cocaine are more likely to be HIV infected than are heroin injectors, differences in the type of drug injected between countries may have distinct epidemiological consequences on the spread of HIV.

[Preliminary study on the presence of arbovirus in the populations of Corrientes and Misiones]

Human seroprevalence of Flavivirus was determined by hemagglutination inhibition tests on 479 sera from Misiones and 49 from Corrientes provinces. Paraná and Uruguay river bank communities from Argentina and neighbouring countries carry out frequent traffic across the rivers. With the aim of searching for a possible introduction of Dengue virus from Brasil or/and Paraguay, reactivity among people from Paraná and Uruguay river communities was compared with those from mountain communities. Two sera from Ituzaingó (Corrientes Province) were positive for Dengue 2. In Misiones, 3 sera from Oberá and 2 from Montecarlo were reactive for Dengue 2 and 1 serum from Puerto Iguazú was reactive for Dengue 1. Seroprevalence among the river population was significatively higher than among the mountain population. Likewise, populations on Paraná river showed more positive sera than those on Uruguay river; 54% of the samples possessed titers for SLE virus higher than for Dengue or Yellow fever. Anti-alphavirus (EEE and WEE) antibodies tested in sera from Misiones people showed a complementary distribution pattern to flavivirus. Seroprevalence of anti-alphavirus antibodies was higher in the mountain than in the river populations.

Etiologic, clinical, and pathologic analysis of 31 fatal cases of acute respiratory tract infection in Argentinian children under 5 years of age

During a 3-year survey of 805 children with acute lower respiratory tract infection (ALRI) who were admitted to three hospitals in Buenos Aires, 31 fatal cases were recorded--a fatality rate of 3.8%. Of the 31 children who died, 77% were less than 1 year of age, 48% were boys, 58% were malnourished, 29% had previous respiratory disease, and 22% had previous congenital disease. All children who died had clinical diagnoses of pneumonia (71%) or bronchiolitis (29%). Autopsies were performed in 14 of the cases. Viral etiology was determined by both cell culture and indirect immunofluorescence (IIF) assay of either nasopharyngeal aspirates (NPA) or lung tissue and bacterial etiology was determined by isolation of organisms from blood, lung tissue, and/or pleural fluid. NPA was examined for Bordetella pertussis by IIF. Pathogens were identified in 65% of fatal cases. Seven cases were bacterial; seven cases were viral; and six cases resulted from mixed infections. Lung tissue yielded positive etiologic results in 10 of 13 cases. Histopathologic examination performed on specimens from the 14 autopsied children revealed necrotizing bronchiolitis with intranuclear inclusions (n = 5) and multifocal pneumonia (n = 9).

Etiologic and clinical evaluation of acute lower respiratory tract infections in young Argentinian children: an overview

This paper summarizes the first study on clinical, etiologic, and epidemiologic features of acute lower respiratory tract infection (ALRI) in children in Argentina. A total of 1,003 children less than 5 years of age (805 inpatients and 198 outpatients) presenting with ALRI were studied during a 40-month period. Nasopharyngeal aspirate (NPA), blood, urine, and throat-swab samples were collected when each child was first seen for care. Virologic studies were performed on the NPA by means of indirect immunofluorescence and isolation of virus in cell culture. Bacteriologic studies primarily were done by means of culture of blood or pleural fluid (when available); Bordetella pertussis and Mycoplasma pneumoniae, however, were searched for by the use of immunofluorescence and complement-fixation testing, respectively, in paired sera. Respiratory syncytial virus was the most commonly isolated virus, followed by adenovirus, parainfluenza virus, and influenza virus. Streptococcus pneumoniae was the most frequently isolated bacterium, followed by B. pertussis and Haemophilus influenzae type b. Overall, the patient fatality rate was 3.8% among inpatients with pneumonia or bronchiolitis.

Epidemiologic risk factors for children with acute lower respiratory tract infection in Buenos Aires, Argentina: a matched case-control study

The risk factors that predisposed 516 hospitalized and 154 ambulatory patients to acute lower respiratory tract infection (ALRI) are examined in a matched case-control study. The control group was selected from children attending immunization and well-baby clinics at the same institution that was treating the children with ALRI. Sex, age, nutritional status, socioeconomic level, as well as season and place of residence were used as matching criteria. Because of their distinct profiles, hospitalized and outpatient groups were analyzed separately. However, the four variables with the highest odds ratios (incidence ratios or relative risk) were found to be the same for both groups. These variables were related to the host's condition (bronchial hyperreactivity, presence of persistent symptoms of the upper respiratory tract), family (presence of acute respiratory tract disease in household members), and environment (indoor contaminants).

Isolation and identification of viral agents in Argentinian children with acute lower respiratory tract infection

From a total population of 1,002 children with acute lower respiratory infection (ALRI), identification of virus was achieved in 304 cases. In this survey, 1,000 nasopharyngeal aspirate and 13 lung tissue samples were tested in four cell lines (HEp-2, MRC-5, MDCK, and LLC-MK2) and by indirect immunofluorescence (IIF), while 242 paired sera were studied by complement fixation. Respiratory syncytial virus (RSV) was the most frequently detected agent (n = 183), followed by adenovirus (n = 28), parainfluenza (n = 5) and 3 (n = 16) viruses, and influenza A (n = 10) and B (n = 4) viruses. The sensitivity and specificity of IIF identification vs. isolation in cell culture were high for RSV (91.5% and 94.9%, respectively). However, IIF proved poorly sensitive for detection of adenovirus (sensitivity, 23.8%; specificity, 100%). The complement-fixation test proved the least effective, with a sensitivity of only 41.5%. Therefore, on the basis of our experience, it appears that the yield for positive diagnosis of virus is increased if both isolation in multiple cell lines and identification by means of IIF are used. Our survey provides for the first time reliable data on the viral etiology of ALRI in Argentina, as determined by three different methods.

[Serologic response measured by complement fixation in children with acute respiratory infection]

The aim of this work was to evaluate the sensitivity of complement fixation for serological diagnosis of lower acute respiratory infections (ARI) in small children in comparison with direct methods such as indirect immunofluorescence (IIF) on nasopharyngeal aspirate and tissue culture isolation. Sera from children under 5 year of age with ARI were studied by complement fixation for 6 respiratory viruses (respiratory syncytial virus (RSV), adenovirus, influenza A and B and parainfluenza 1 and 3). In all, 264 pairs of serum samples from children with viral ARI diagnosis (n:135) or from doubtful cases (n:90) were studied. Thirty nine sera were anticomplementary. In samples from confirmed viral ARI patients, seroconversion was detected in 38%, whereas from those with a doubtful diagnosis it was only 14%. Seroconversion for RSV and adenovirus was 39% and 50%, respectively. On correlating seroconversion for the 6 viruses according to age group, 20% positivity was found in the 0-5 month-old group, 35% in the 6-10 month-old and 30% in those over 11 months of age. For RSV alone, 0-5 month-old patients presented 25% seroconversion, and in those over 6 months of age the percentage exceeded 60% (p less than 0.001). Complement fixation test sensitivity vs direct methods (IIF and/or culture) was 38.5%). Our findings confirm the low sensitivity of complement fixation to detect antibodies in ARI, particularly in children under 6 months of age and support the higher efficacy of direct diagnostic methods. However, complement fixation serology is useful for epidemiological studies in children over 6 months of age, since over 60% of RSV were readily detected.

Viral etiology in acute lower respiratory infections in children from a closed community

The aim of this study was to determine the viral agents associated with acute lower respiratory infections (ALRI) in young children. During a 2-yr period, 204 nasopharyngeal aspirates (NPA) from children under 4 yr of age living in an orphanage and exhibiting febrile ALRI were studied by both indirect immunofluorescence (IIF) and isolation in four cell lines. NPA cell smears as well as tissue culture cells exhibiting cytopathic effect (CPE) or hemadsorption were stained by IIF for respiratory syncytial virus (RSV), adenovirus, influenza A and B, and parainfluenza 1 and 3. Viral etiology was demonstrated in 21.2% of acute respiratory infection cases. The most frequently detected virus was RSV (53.5% of viral positive diagnoses), followed by unidentified viruses (18.6%), adenovirus (13.9%), influenza A (7%), and parainfluenza 3 (4.7%). The most common clinical entities were: bronchitis, 46.1%; pneumonia, 24%; bronchiolitis, 22%; and multifocal pneumonia, 8%. Malnourishment was found in 56% of children with ALRI, whereas 50% was found among total orphanage population. The 3 to 8-month-old age group accounted for half of all ALRI cases. Viral etiology was shown for 26.5% of patients with pneumonia, 22% with bronchitis, and 16% with bronchiolitis. RSV and adenovirus occurred in fall and winter, while parainfluenza 3 was detected in early spring. In the two fatal cases observed, histologic lesions were compatible with adenovirus infection, but this virus could be isolated from the lung in only one case.

Calomys callidus as a potential Junin virus reservoir

The present study investigated whether C. callidus, a species belonging to the Calomys genus, is capable of developing experimentally a persistent Junin virus (JV) infection. Newborn and adult cricetids were inoculated with the attenuated XJ-Clone 3 strain of JV by intracerebral or mucosal route. The present results indicate that the species is susceptible to JV infection, capable of shedding virus chronically through saliva and developing a persistent infection as shown by the detection of virus in brain tissue at 60 days post infection. These findings, and the fact that this cricetid shares its distribution areas with Calomys musculinus and Akodon azarae, support C. callidus as a potential JV reservoir.

[Antigenic variants of the respiratory syncytial virus in Argentina and Uruguay]

The characterization of RSV antigenic variants was carried out on 160 nasopharyngeal aspirates from children under 5 years of age, from Argentina and Uruguay, with acute respiratory infection and a previously positive etiological diagnosis for RSV. Results for Argentina were: 20.9% of samples belonged to subtype A, 76.9% to subtype B and the remaining 2.2% to new subtypes as yet uncharacterized. Results for Uruguay were: 5.6% of samples belonged to subtype A, 81% to subtype B and 13.5% to other subtypes. Subtype B was predominant in both countries. The correlation of RSV antigenic variants with the clinical picture and epidemiological profile is currently underway.