Seroepidemiological associations between tuberculosis, malaria, hepatitis B, and AIDS in West Africa

Estimating Prevalence of Hepatitis B Virus Coinfection Among Adults With Tuberculosis: A Systematic Review With Meta-analysis

BACKGROUND

While patients with hepatitis B virus (HBV) infection and tuberculosis (TB) have similar risk factors, little is known regarding the prevalence of HBV and TB coinfection. We aim to evaluate the prevalence of HBV among patients with TB across world regions.

METHODS

We systematically reviewed the literature using PubMed from inception through September 1, 2019, to identify studies that provided data to calculate HBV coinfection prevalence among adults with TB infection. Prevalence estimates of HBV coinfection among TB patients were stratified by world regions and calculated using meta-analyses with random-effects models.

RESULTS

A total of 36 studies met inclusion criteria (4 from the Africa region, 6 from the Americas region, 5 from the Eastern Mediterranean region, 2 from European region, 6 from Southeast Asia region, and 13 from the Western Pacific region). On meta-analysis, overall pooled HBV coinfection prevalence among TB patients was 7.1%, but varied by world region. Region-specific pooled HBV prevalence among TB patients was highest in Africa region [11.4%, 95% confidence interval (CI): 3.45-19.31] and Western Pacific region (10.8%, 95% CI: 8.68-12.84), and was lowest in the Americas (2.2%, 95% CI: 0.78-3.53). Sensitivity analyses yielded similar HBV prevalence estimates across world regions.

CONCLUSIONS

In this meta-analysis, we observed HBV coinfection prevalence among TB patients to be 38% to 450% higher than published estimates from the Polaris group of region-specific overall HBV prevalence. Timely identification of HBV infection among TB patients will improve patient outcomes by allowing for closer clinical monitoring and management, which may reduce the risk of liver dysfunction and liver failure related to TB treatment.

Prevalence of Malaria and TB Coinfection at a National Tuberculosis Treatment Centre in Uganda

The prevalence of malaria and tuberculosis (TB) coinfection is not well established in countries that are highly burdened for both diseases. Malaria could impair TB containment and increase mortality of TB patients. The objective of this study was to determine the prevalence of malaria/TB coinfection among bacteriologically confirmed adult TB patients at a national TB treatment centre in Uganda. Using a cross-sectional study design we enrolled 363 bacteriologically confirmed adult TB patients, and data on demographics and medical history was collected. Blood samples were tested for malaria blood smear, rapid malaria diagnostic test (RDT), complete blood count, haematological film analysis, HIV serology, and CD4+ and CD8+ cell counts. Malaria was defined as either a positive blood smear or RDT. The study participants were mostly male (61.4%), with a median age of 31 (interquartile range, IQR: 25-39) years, and 35.8% were HIV positive. The prevalence of malaria was 2.2% (8/363) on the overall and 5% (3/58) among participants with rifampicin resistance. A triple infection of HIV, malaria, and rifampicin resistant TB was observed in 3 participants. The prevalence of malaria among TB patients is low, and further evaluation of the epidemiological, clinical, and immunological interaction of the two diseases is warranted.

The search for a tuberculosis vaccine: An elusive quest?

The precise mechanisms of protective immunity and pathogenesis of tuberculosis (TB) are poorly understood. Yet, many efforts are underway to develop new, more effective vaccines against Mycobacterium tuberculosis. This development appears to be predicated upon the assumption that natural acquired immunity to TB exists. In this paper we review the evidence for such immunity, explore the hypothesis that disease progression is due to some, often transient, immunological dysfunction, and discuss its relevance for vaccine development. Several mechanisms for such an immune dysfunction are proposed, including the recently suggested involvement of viral co-infections. Developing vaccines for such co-infections may be a new challenge for TB control.

Jaundice in malaria

Jaundice is not an unusual accompaniment of malaria. It can occur due to intravascular hemolysis, disseminated intravascular coagulation, and, rarely, 'malarial hepatitis'. Although the primary schizogony of the malarial parasite always leads to the rupture of the infected hepatocyte, alteration of the hepatic functions is uncommonly recorded due to this event. Histologically, the hepatitis or the actual inflammation in the liver has never been demonstrated. Nonetheless, the term 'malarial hepatitis' (MH) has been used in the literature to describe the occurrence of hepatocellular jaundice in patients with Plasmodium falciparum infection. The authors' own data and review of the literature indicate that it is not an uncommon entity. In endemic areas, jaundice is seen in approximately 2.5% of patients with falciparum malaria. It also appears to be a heterogeneous syndrome and one can recognize two clinical subsets. In one group there was an acute, virulent presentation with coma, renal failure and in some cases even hemorrhagic manifestations. It is only in this setting that jaundice signified a 'severe' disease as noted by the World Health Organization action program. This presentation is often confused with acute viral hepatitis and acute hepatic failure in non-endemic areas, but can be clinically differentiated.

Management of HIV-infected pregnant patients in malaria-endemic areas: therapeutic and safety considerations in concomitant use of antiretroviral and antimalarial agents

Chemotherapy in pregnancy is an intricate process requiring prudent use of pharmacologic agents. Malarial infection during pregnancy is often fatal, and prophylaxis against the causative parasite necessitates rational therapeutic intervention. Various agents have been used for prophylaxis against malaria during pregnancy, including chloroquine, mefloquine, proguanil, pyrimethamine, and pyrimethamine-sulfadoxine. Use of these agents has been based on a risk-benefit criterion, without appropriate toxicologic or teratologic evaluation. Some of the aforementioned prophylactic agents have been shown to alter glutathione levels and may exacerbate the oxidation-reduction imbalance attendant on HIV infection. HIV-infected patients traveling to or residing in malaria-endemic areas require protection from malarial infection to avoid placing themselves in double jeopardy. Zidovudine (AZT) is recommended for the prevention of vertical transmission of HIV-1 from mother to child. Other agents, such as lamivudine alone or in combination with AZT, nevirapine, or the HIV-1 protease inhibitors, are either being considered or are currently undergoing trials for use in preventing vertical transmission of HIV-1 or managing HIV infection in infants and children. Although the potential for antimalarial agents to cause congenital malformations is low when they are used alone, their ability to cause problems when combined with antiretroviral drugs needs to be evaluated. In developing countries that have high birth rates, a high endemicity of malaria, and alarming rates of new cases of HIV, prophylaxis against both diseases with combination agents during pregnancy is a challenge.

Seroprevalence and coprevalence of HIV and HBsAg in Nigerian children with/without protein energy malnutrition

In order to assess the seroprevalence and coprevalence of hepatitis-B surface antigen (HBsAg), human immunodeficiency virus-1 and -2 (HIV-1 and -2) antibodies in Nigerian children with/without protein energy malnutrition (PEM), we studied plasma specimens of 206 children with PEM and 200 apparently healthy reference children aged between 1 and 3 years by enzyme-linked immunosorbent assays (ELISA). HIV-seropositive cases were confirmed by immunoblotting (IB). Of the children studied, eight (4%) of the healthy and four (1.9%) of the malnourished (P = 0.22, Fisher's exact test) were positive for HIV-1 antibodies, 40 (20%) of the healthy and 54 (26%) of the malnourished (P = 0.14) were positive for HBsAg, and five (2.5%) of the healthy and four (1.9%) of the malnourished (P = 0.70) were positive for both HIV-1/HBsAg. No case of HIV-2 antibodies was found. While the seroprevalence of HBsAg was higher in the malnourished subjects, the reverse was the case with HIV antibodies. However, all the four HIV-1-positive malnourished children and five of eight of the HIV-1-positive reference children were simultaneously positive for HBsAg. This is the first epidemiological report on the seroprevalence and coprevalence of HIV and HBsAg in apparently healthy and malnourished Nigerian children.