Risk of progression to active tuberculosis among foreign-born persons with latent tuberculosis.

BACKGROUND: Increased risk for tuberculosis (TB) disease has been identified in foreign-born persons in the United States, particularly during the first 5 years after their arrival in the United States. This could be explained by undetected TB disease at entry, increased prevalence of latent TB infection (LTBI), increased progression from LTBI to TB, or a combination of these factors. METHODS: We performed a cluster analysis of TB cases in Boston and a case-control study of risk factors for TB with an unclustered isolate among Boston residents with LTBI to determine whether such persons have an increased risk for reactivation of disease. RESULTS: Of 321 case patients with TB seen between 1996 and 2000, 133 isolates were clustered and 188 were not. In multivariate analysis, foreign birth was associated with an unclustered isolate (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.2 to 3.8; p < 0.01), while being a close contact of a TB case was negatively associated (OR, 0.22; 95% CI, 0.07 to 0.73; p = 0.02). When 188 TB patients with unclustered isolates were compared to 188 age-matched control subjects with LTBI, there was no association between the occurrence of TB and foreign birth (OR, 0.71; 95% CI, 0.42 to 1.3); among foreign-born persons, there was no association between the occurrence of TB and being in the United States

Protective correlates against HIVs may have evolved in human populations in the areas of historic occurrence of primate-to-man transmissions of SIVs ancestral to HIVs: studies in these populations may provide crucial insights for treatment and prevention of HIV infection.

Recent findings suggest that Human Immunodeficiency Viruses, HIV-1 and 2, might have been transmitted to humans from particular primate species. It is thought that some Simian Immunodeficiency Viruses (SIVs), from which HIVs presumably originated, existed in their primate hosts for ages. Behavioral characteristics increasing the probability of contact between these primates and humans (such as keeping monkeys for pets, hunting monkeys for food, improper handling of the monkey meat, etc.) documented in some African countries could have facilitated cross-species transmissions (CSTs) of HIVs. As it has been shown, multiple CSTs took place for both HIVs (1 and 2) and then, in a globalizing world, these local events led to the pandemic. Here, it is brought forward that in the regions of epizooty of SIVs closely related to HIVs, some human populations might have had exposure history to these viruses dating back hundreds years. Lacking the important framework for further spread provided by nowadays globalization, these CSTs could have led to isolated local HIV outbreaks limited to particular tribes or groups. The infections could have extinguished some populations while on the other hand provided evolutionary pressure to select for mechanisms protective for HIV infection and/or disease. Thus, here it is hypothesized that in the areas of the habitat of primates infected with SIVs, from which HIVs are thought to be originated, there could be historically exposed populations which might possess biological correlates of protection from HIVs. Current knowledge on the distribution of primates hosting HIV-related SIVs suggests that epidemiological, primatological, anthropological and molecular biological studies in the areas of Cameroon, Gabon, both Congos and Equatorial Guinea (for HIV-1) and Guinea-Bissau, Senegal, Guinea, Ivory Cost, Sierra Leone and Liberia (for HIV-2) could lead to the discoveries of correlates of protection against HIVs. It is also hypothesized that virology studies in the same areas might reveal less virulent and/or infective viruses which could provide insights in the HIV pathogenesis and vaccinology.

Predictors of failure to complete treatment for latent tuberculosis infection.

OBJECTIVE: Low rates of completion of treatment for latent tuberculosis infection (LTBI) limit its usefulness as a strategy for elimination of tuberculosis (TB) in the United States. This retrospective cohort study assessed predictors of completion of LTBI treatment among patients seen at an urban United States TB clinic in 1998. METHODS: A retrospective cohort study of acceptance and completion of LTBI treatment among patients first seen in a TB clinic in 1998 was performed. RESULTS: Of 2621 persons with a positive tuberculosis skin test (TST), 1723 were offered treatment and 1572 (91.2%) accepted. Of the 1572 who accepted, treatment was completed by 607 (38.6%). Of those persons who failed to complete treatment, 517/965 (54%) dropped out before the end of the first month of the course. Among 1375 persons under 35 years of age who initiated LTBI treatment, failure to complete was associated with birth in Haiti (OR=2.17, CI(95%) 1.49-3.17) or the Dominican Republic (OR=1.93, CI(95%) 1.08-3.43). CONCLUSION: These results suggest that country-specific cultural and behavioral factors may contribute to failure to complete LTBI treatment, and that interventions to increase completion should focus on the first month after initiation.