Cryptococcosis in Africa: What the data tell us

Lay Summary Cryptococcosis is a neglected tropical disease that manifests greatly in immunocompromised persons especially those with HIV infection. Our data show that managing cryptococcosis will require an integrated multidisciplinary approach that should include the utilisation of cryptococcal antigen (CrAg) testing, which is highly sensitive and cost-effective for diagnosing this disease. Cryptococcosis is a neglected tropical disease and the main cause of fungal-related deaths in HIV-positive persons in Africa. It is an AIDS-defining illness that has almost surpassed tuberculosis (TB) in mortality despite wide coverage with antiretroviral therapy. What is known about the cryptococcosis burden in Africa is from estimations based on data from a few studies on the infection burden and associated complications. Consequently, the projected implications of cryptococcosis in Africa have been based on these estimations. This systematic review is aimed at providing unique and up-to-date data on the burden of cryptococcosis in Africa using published hospital-based research data on cryptococcosis in HIV infected and uninfected persons. The review also focused on providing temporal data on the availability of diagnostic and therapeutic options for cryptococcosis in Africa. From our results, about 40 948 cases of cryptococcosis were reported in Africa from 1969 to 2021, and the highest prevalence of cryptococcosis was from southern Africa. The most isolated species was Cryptococcus neoformans 42.4% (17 710/41 801) and only 1.3% (549/41 801) isolates were C. gattii. C. neoformans (serotype A) VN I 64.5% (918/1522) was the most prevalent serotype in Africa, while C. gattii (serotype C) VG IV was thought to pose a huge danger. However, C. neoformans (serotype A) VN I continued to be the major threat in Africa. Due to the limited availability of molecular typing methods and the widespread use of culture, direct microscopy, and serological techniques for diagnosis, 23 542 isolates were uncharacterised. Amphotericin B and flucytosine combination therapy is highly recommended for treatment of cryptococcal meningitis. However, these drugs are expensive and remain largely unavailable in most African countries. Amphotericin B requires laboratory facilities to monitor for toxicity. Although fluconazole monotherapy is the readily available treatment option for cryptococcosis, drug resistance, and high mortality have been recorded in majority of cases in Africa. The lack of awareness and paucity of published data on cryptococcosis are likely to have contributed to the underestimation of cases in Africa and led to underprioritisation of this important disease.