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Objectives: Trypanosoma cruzi reactivation in HIV patients is considered an opportunistic infection, usually with a fatal outcome. The aim of this study was to describe the epidemiological and clinical features of T. cruzi infection in HIV patients and to compare these findings between patients with and without Chagas disease reactivation. Methods: The medical records of T. cruzi–HIV co-infected patients treated at the Muñiz Infectious Diseases Hospital from January 2005 to December 2014 were reviewed retrospectively. Epidemiological and clinical features were assessed and compared between patients with and without Chagas disease reactivation. Results: The medical records of 80 T. cruzi–HIV co-infected patients were reviewed. The most likely route of T. cruzi infection was vector-borne (32/80 patients), followed by intravenous drug use (12/80). Nine of 80 patients had reactivation. Patients without reactivation had a significantly higher CD4 T-cell count at diagnosis of T. cruzi infection (144 cells/μl vs. 30 cells/μl, p = 0.026). Chagas disease serology was negative in two of nine patients with reactivation. Conclusions: Serological assays for T. cruzi infection may be negative in severely immunocompromised patients. Direct parasitological techniques should be performed in the diagnosis of patients for whom there is a suspicion of T. cruzi reactivation. HIV patients with a lower CD4 count are at higher risk of reactivation. Fil: Benchetrit, Andres Guillermo. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentina Fil: Fernández, Marisa. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentina Fil: Bava, Amadeo Javier. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentina Fil: Corti, Marcelo. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentina Fil: Porteiro, Norma. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentina Fil: Martinez Peralta, Liliana A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina

HIV-1 infection in children less than 15 years of age is mainly due to mother-to-child transmission. The aim of this work was to investigate molecular evidence to prove father-to-be horizontal transmission in two possible events of transmission. In the first event a boy was identified as HIV infected at 2-3 years of age. At the same time infection was confirmed in the father, while mother and siblings were negative. In the second event a girl was negative for HIV at age 1 and identified as HIV-1 infected at age 6. The father's HIV infection was diagnosed in the same period while the mother was repeatedly negative. No evidence of sexual assault or transfusion was recorded in any case. Peripheral blood mononuclear cells were obtained from both fathers and children. After PCR amplification, the C2V3 region of the envelope gene and the region coding for amino acid 132 of p24 up to amino acid 40 of p7 of the gag gene were sequenced. Genetic distance measurements and phylogenetic tree analysis showed that in both cases the father's and child's viral sequences were closely related. They were distinct when compared to Argentina sequences including sequences from the same geographic region. Epidemiological and molecular data strongly suggest that horizontal transmission had occurred, probably related to the close father-to-child contact.

The presence of recombinant intersubtypes of HIV-1 in Argentina has been reported since the mid-1990s. In this study sequences of a region of the gag pol and vpu genes of HIV-1 were analyzed in samples of 21 injection drug users (IDUs) residing in the suburbs of the city of Buenos Aires. Genomic characterization and identification of recombination sites were made comparing the 3 regions with reference isolation sequences of subtypes B F C A and B/F recombinants: CRF12_BF and non-CRF12_BF sequences. Subtype assignment of the analyzed segments was phylogenetically confirmed. All the samples turned out to be BF recombinants in at least 1 of the 3 studied genes. Twelve samples (57%) had the same pattern as the Argentinean CRF12_BF whereas in the rest the pattern differed in at least 1 of the 3 genes. The relation of these fragments to the CRF12_BF was phylogenetically verified. These results indicate the predominance of BF recombinants and the presence of a high percentage of sequences closely related to the CRF12_BF in the IDU population in Argentina and suggest a possible association between viral variants and the transmission route. (excerpt)

This study evaluated the success of a national program for the prevention of mother-to-child transmission (MTCT) of HIV-1 in 874 mother-infant pairs from Buenos Aires and surroundings. This population was referred to the National Reference Center for AIDS for diagnosis of neonatal infection during 1993-2000. The data revealed an increase in the use of antiretroviral therapy during pregnancy from 3.2% in 1993-1994 to 73.1% in 1999-2000 and in the use of cesarean delivery (reaching 54.8% in 1999-2000). However, the proportion of HIV-infected women who continued to breast-feed their children remained steady (around 12%). General improvement of the conditions for decreasing MTCT resulted in a significant decrease in the proportion of infected infants from 37.3% before 1995 to 10.7% in 1999-2000 and even 6.5% during 2001. Data on the time of diagnosis indicated that only 42.7% of the women knew about their HIV status before pregnancy, 44.8 knew during pregnancy, and 12.3% knew after the birth of their child. The main risk factor for HIV infection in the mothers was heterosexual contact (73%), and in the fathers, it was injection drug use (67%). These results point out the urgent need to develop additional strategies for prevention of MTCT of HIV-1 to generalize education, counseling, and testing of young women.

This study determined the risk behaviors and viral subtypes of HIV-1 found in 134 heterosexual HIV-seroprevalent maternity patients, 41 of their sexual partners (men who have sex with women [MSW]), and 95 homosexual men (men who have sex with men [MSM]) from Buenos Aires, Argentina. Peripheral blood mononuclear cells (PBMCs) were purified from blood and used for DNA extraction, amplification, and genotyping by the envelope heteroduplex mobility assay (env HMA). Most of the women had been infected by having sex with an already infected partner (84%), whereas most of the male partners had been infected via drug use (76%). Both the patients and their sexual partners were poorly educated, only 30% having completed secondary school. The MSM study subjects, however, were significantly better educated and had a lower prevalence of injecting drug use.Env HMA subtype F was found in 77% (103 of 134) of the maternity patients, with similar rates in their partners (73%). Most of the remaining samples were env subtype B. All but one of the couples was concordant in subtype. In the MSM risk group, however, only 10% were env HMA subtype F. Ninety percent of the MSM samples were subtype B. There are at least two independent epidemics of HIV-1 infection in Buenos Aires, Argentina. One, in heterosexual men and women, is dominated by env subtype F whereas the other, in homosexual men, is dominated by env subtype B, as determined by env HMA.

Background Genetic characterization of HIV-1 in Argentina has shown that BF recombinants predominate among heterosexuals and injecting drug users, while in men who have sex with men the most prevalent form is subtype B. Objectives The aim of this work was to investigate the presence of HIV dual infections in HIV-infected individuals with high probability of reinfection Study design Blood samples were collected from 23 HIV positive patients with the risk of reinfection from Buenos Aires. A fragment of the HIV gene pol was amplified and phylogenetic analyses were performed. Antiretroviral drug resistance patterns of all the sequences were analyzed. Results Five dual infections were detected with four patients coinfected with subtype B and BF recombinants and one patient was coinfected with two BF recombinants presenting different recombination patterns. Prolonged infection with a stable clinical condition was observed in the five individuals. Resistance mutation patterns were different between the predominant and the minority strains. Conclusions Our results show that HIV dual infection can occur with closely related subtypes, and even with different variants of the same recombinant form in certain populations. Clinical observations showed neither aggressive disease progression nor impact on the resistance patterns in the dually-infected patients.

Conclusion These results correlate with previous studies conducted among IDUs from New York city, Vietnam and Southern Europe where HTLV-IIb was more frequently found. In contrast, IIa is found among IDUs from other regions of the USA, Europe and Brazil. This is the first time in which subtype b is described in Argentina among IDUs. Its presence may be due to migrations of aborigines to big cities and the introduction of drugs in this population. Lately, there was also a high rate of migration and tourism to Argentina, especially from southern Europe and USA, possibly contributing to the spread of HTLV-IIb in our country. Interestingly, the IIa sample described here was found to be related with Brazilian aborigine sequences in contrast to the previous Argentinian IDU which was closer to African isolates. from 2006 International Meeting of The Institute of Human Virology Baltimore, USA. 17–21 November, 2006

Injection drug use is the main mechanism of human immunodeficiency virus (HIV) transmission in Argentina (40% of reported AIDS cases in Argentina). This study was conducted among street-recruited injection drug users (IDUs) from Buenos Aires, with the aim of estimating seroprevalence and coinfection of HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), and human T-lymphotropic viruses (HTLVs). A total of 174 volunteers participated in this study; 137 were men (78.7% of volunteers). The average age of the participants was 30 years. Only 64 of participants (37%) had no viral infection, whereas 110 (63%) were infected with > or =1 viruses. Seroprevalences were 44.3% for HIV, 54.6% for HCV, 42.5% for HBV, 2.3% for HTLV-I, and 14.5% for HTLV-II. Among the 77 HIV-infected persons, only 6.5% (5 persons) were not coinfected with other viruses; 88.3% (68) were coinfected with HCV and 68.8% (53) were coinfected with HBV. We demonstrated the existence of multiple viral infections with a high rate of prevalence in IDUs in Buenos Aires, Argentina.

Detection of anti-HIV-1 IgA antibodies using a modified ELISA test for the early diagnosis of perinatally acquired HIV-1 infection in children treated with protocol ACTG 076 was evaluated. A total of 177 sera were obtained from 141 infants between 1 and 12 months of age (46 were treated and 95 were non-treated with protocol ACTG 076) and tested for HIV IgA antibodies by an ELISA test after removal of IgG with recombinant protein G. Infants were classified according to CDC's classification system after a follow-up until 20 months of age. Of the 46 treated children 22 turned out to be infected and in the group of 95 untreated children, 52 were infected. All 81 samples from uninfected children treated or untreated with protocol ACTG 076 were persistently IgA-negative. HIV IgA antibodies were detected in 14 of 25 plasma samples from infected children with treatment, and in 58 of 71 samples in infected children without treatment. Considering that the sensitivity of this test is lower in children younger than 6 months the population of children studied was divided into two groups; those under and those over 6 months of age. No significant differences were observed in the detection of IgA in treated or untreated children in both age groups. The overall specificity of the test was 100 per cent; sensitivity in children older than 6 months was 76.92 per cent in treated children and 93.10 per cent in untreated children. In spite of the small number of samples studied it could be demonstrated that treatment with zidovudine does not affect the detection of IgA antibodies. This is a simple and inexpensive method that could be used for diagnosis of treated and untreated children in developing countries.

Address: 1National Reference Centre for AIDS, Microbiology Department, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina, 2Laboratory of Parasitology, Microbiology Department, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina and 3Endocrinology Service, Clinic Biochemistry Department, Jose de San Martin Hospital, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina * Corresponding author

In this article we describe two lethal cases of MTCT of HIV and T.cruzi in the province of Buenos Aires, Argentina. Child 1 was admitted to the hospital being 1 month old with respiratory difficulty and diarrhoea. Being six months old he was released but being 22 months old he presented sepsis and died. The mother was not treated during pregnancy, while the child was treated with combined HAART and benznidazol. Child 2 was admitted to a provincial Hospital being 20 days old, and referred to the Children´s Hospital. After 39 days at the ICU the child died with sepsis. His mother received ZDV late in her pregnancy. The child received was treated with HAART, interrupted at 3 months due to severe organic failure. The lack of diagnosis of T. cruzi in both mothers worsened the prognosis of these two children, since treatment with antiparasitic drugs is used since birth. Fil: Agosti, Maria Rosa. Hospital de Niños Sor María Ludovica, la Plata; Argentina Fil: Ercoli, Pablo. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia para el Sida; Argentina Fil: Dolcini, Guillermina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia para el Sida; Argentina Fil: Andreani, Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia para el Sida; Argentina Fil: Martinez Peralta, Liliana A.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología; Argentina Fil: Gonzalez Ayala, Silvia Elena. Hospital de Niños Sor María Ludovica, la Plata; Argentina

Background HIV triggers the decline of CD4+ T cells and leads to progressive dysfunction of cell-mediated immunity. Although an increased susceptibility to cell death occurs during the acute phase of HIV infection, persistently-infected macrophages and quiescent T-cells seem to be resistant to cell death, representing a potential reservoir for virus production. Results Lymphoid (H9/HTLVIIIB and J1.1) and pro-monocytic (U1) HIV-1 persistently-infected cell lines were treated with hydrogen peroxide (H2O2) and staurosporine (STS) for 24 h, and susceptibility to apoptosis was evaluated and compared with uninfected counterparts (H9, Jurkat and U937 respectively). When exposed to different pro-apoptotic stimuli, all persistently-infected cell lines showed a dramatic reduction in the frequency of apoptotic cells in comparison with uninfected cells. This effect was independent of the magnitude of viral replication, since the induction of viral production in lymphoid or pro-monocytic cells by exposure to TNF-α or PMA did not significantly change their susceptibility to H2O2- or STS-induced cell death. A mechanistic analysis revealed significant diferences in mitochondrial membrane potential (MMP) and caspase-3 activation between uninfected and persistently-infected cells. In addition, Western blot assays showed a dramatic reduction of the levels of pro-apototic Bax in mitochondria of persistently-infected cells treated with H2O2 or STS, but not in uninfected cells. Conclusion This study represents the first evidence showing that resistance to apoptosis in persistently-infected lymphoid and monocytic cells is independent of active viral production and involves modulation of the mitochondrial pathway. Understanding this effect is critical to specifically target the persistence of viral reservoirs, and provide insights for future therapeutic strategies in order to promote complete viral eradication.

Background Several factors determine the risk of HIV mother-to-child transmission (MTCT), such as coinfections in placentas from HIV-1 positive mothers with other pathogens. Chagas' disease is one of the most endemic zoonoses in Latin America, caused by the protozoan Trypanosoma cruzi. The purpose of the study was to determine whether T. cruzi modifies HIV infection of the placenta at the tissue or cellular level. Results Simple and double infections were carried out on a placental histoculture system (chorionic villi isolated from term placentas from HIV and Chagas negative mothers) and on the choriocarcinoma BeWo cell line. Trypomastigotes of T. cruzi (VD lethal strain), either purified from mouse blood or from Vero cell cultures, 24 h-supernatants of blood and cellular trypomastigotes, and the VSV-G pseudotyped HIV-1 reporter virus were used for the coinfections. Viral transduction was evaluated by quantification of luciferase activity. Coinfection with whole trypomastigotes, either from mouse blood or from cell cultures, decreased viral pseudotype luciferase activity in placental histocultures. Similar results were obtained from BeWo cells. Supernatants of stimulated histocultures were used for the simultaneous determination of 29 cytokines and chemokines with the Luminex technology. In histocultures infected with trypomastigotes, as well as in coinfected tissues, IL-6, IL-8, IP-10 and MCP-1 production was significantly lower than in controls or HIV-1 transducted tissue. A similar decrease was observed in histocultures treated with 24 h-supernatants of blood trypomastigotes, but not in coinfected tissues. Conclusion Our results demonstrated that the presence of an intracellular pathogen, such as T. cruzi, is able to impair HIV-1 transduction in an in vitro system of human placental histoculture. Direct effects of the parasite on cellular structures as well as on cellular/viral proteins essential for HIV-1 replication might influence viral transduction in this model. Nonetheless, additional mechanisms including modulation of cytokines/chemokines at placental level could not be excluded in the inhibition observed. Further experiments need to be conducted in order to elucidate the mechanism(s) involved in this phenomenon. Therefore, coinfection with T. cruzi may have a deleterious effect on HIV-1 transduction and thus could play an important role in viral outcome at the placental level.