Invasive Fungal Diseases in Africa: A Critical Literature Review

Invasive fungal diseases (IFDs) are of huge concern in resource-limited settings, particularly in Africa, due to the unavailability of diagnostic armamentarium for IFDs, thus making definitive diagnosis challenging. IFDs have non-specific systemic manifestations overlapping with more frequent illnesses, such as tuberculosis, HIV, and HIV-related opportunistic infections and malignancies. Consequently, IFDs are often undiagnosed or misdiagnosed. We critically reviewed the available literature on IFDs in Africa to provide a better understanding of their epidemiology, disease burden to guide future research and interventions. Cryptococcosis is the most encountered IFD in Africa, accounting for most of the HIV-related deaths in sub-Saharan Africa. Invasive aspergillosis, though somewhat underdiagnosed and/or misdiagnosed as tuberculosis, is increasingly being reported with a similar predilection towards people living with HIV. More cases of histoplasmosis are also being reported with recent epidemiological studies, particularly from Western Africa, showing high prevalence rates amongst presumptive tuberculosis patients and patients living with HIV. The burden of pneumocystis pneumonia has reduced significantly probably due to increased uptake of anti-retroviral therapy among people living with HIV both in Africa, and globally. Mucormycosis, talaromycosis, emergomycosis, blastomycosis, and coccidiomycosis have also been reported but with very few studies from the literature. The emergence of resistance to most of the available antifungal drugs in Africa is yet of huge concern as reported in other regions. IFDs in Africa is much more common than it appears and contributes significantly to morbidity and mortality. Huge investment is needed to drive awareness and fungi related research especially in diagnostics and antifungal therapy.

Epidemiology of Cryptococcus and cryptococcosis in Western Africa

Cryptococcosis is a serious and sometimes fatal fungal disease caused by Cryptococcus species. Worldwide, it is estimated to kill over 180 000 annually, with 75% of deaths occurring in sub-Saharan Africa. Though cryptococcal infections are rare in otherwise healthy individuals, there have been reported cases in immunocompetent persons. Most cases occur in individuals who have weakened immune systems, particularly those with advanced HIV/AIDS, thus making West Africa a potential hotspot of the disease. Despite this, there is no recent review article with a focus on published findings on cryptococcosis in Western Africa. Common clinical symptoms include chest pain, dry cough, headache, nausea, confusion, fever, fatigue and stiffness of the neck/neurological impairment. The CNS and the lung remain its preferred target even though rare cases of attack on other parts of the body were reported in this review. Cryptococcal antigen screening and India ink preparation were the most commonly used diagnostic methods. Repeated isolation from environmental samples was observed. Overall, data on the clinical prevalence of Cryptococcus are scarce and variable in the region. The environmental prevalence ranges from 2.3% to 22%. This review covers all published research findings on cryptococcosis in West Africa till date. The epidemiological data will likely be of interest to clinicians within and outside the continent. The nations covered in this review include the following: Benin Republic, Burkina Faso, Cote d'ivoire, Ghana, Guinea, Guinea- Bissau, Mali, Nigeria, Senegal and Sierra Leone. More studies are warranted to fill the observed gaps on the epidemiology of Cryptococcus in the region.

Cryptococcus neoformans seropositivity and some haematological parameters in HIV seropositive subjects

BACKGROUND

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningitis worldwide and may be fatal in immunocompromised subjects. In Nigeria, cases have been reported with prevalence between 4 and 13.1% in Human Immunodeficiency virus (HIV) patients depending on the study subjects. This study was designed to assess the prevalence of cryptococcosis, CD4+T cell counts and possible effect on haematological parameters in HIV seropositive subject in Nnewi, South-Eastern Nigeria.

METHOD

A total of four hundred and twenty-nine (429) subjects were recruited for the study. Of these, two hundred and ninety (290) were HIV positive and one hundred and thirty-nine (139) were HIV seronegative subjects recruited from the voluntary counseling and testing (VCT) unit and HIV care clinic at Nnamdi Azikiwe University Teaching Hospital Nnewi, Anambra State, Nigeria. Their ages were between 18-80 years. One hundred and thirty nine (139) apparently healthy HIV seronegative subjects were recruited as controls. Blood samples were taken for C. neoformans by Antigen lateral flow assay (CrAgLFA), HIV testing, CD4+T cell, platelet and Full blood count (FBC).

RESULTS

Our results show that of the two hundred and ninety (290) who were HIV positive subjects investigated for cryptococcosis, 4 (1.4%) tested positive for CrAg of whom 1(25%) were male and 3(75%) were female. All those with cryptococcosis had their CD4 count below 200 cells/μL, three of them were on ART and one was not. There were significant differences in the CD4 counts (P<0.05) between those infected and not infected with C. neoformans. None of the control group tested positive to cryptococcosis.

CONCLUSION

Widespread use of anti-retroviral therapy may have reduced C. neoformans infection. However, the threat remains and there may be a possibility that women may be a more vulnerable population.