ISOLATION OF Cryptococcus neoformans FROM ENVIRONMENTAL SAMPLES COLLECTED IN SOUTHEASTERN NIGERIA

Abstract

SUMMARYCryptococcosis caused by Cryptococcus neoformans is the second most common fungal opportunistic pathogen and a lifethreatening infection with serious clinical manifestations especially in HIV/AIDS and other immunocompromised patients. In Nigeria, HIV/AIDS infection has reached an alarming level. Despite this, information on the presence of this fungus in clinical and environmental samples is very scanty in Nigeria and many other parts of Africa. We set out to evaluate the presence of Cryptococcus neoformans or C. gattii in pigeon droppings obtained from Southeastern Nigeria. One hundred and seventy-seven samples of pigeon droppings from six sample types were collected. The area covered comprised of ten cities and other locations spanning across five States in Nigeria. Using established techniques, Cryptococcus neoformans was isolated from 39 of the 177 (22.0%) samples overall. No C. gattiiwas isolated. Most of the isolates (32.4%) were recovered from dovecotes (11 of 34) followed closely by samples taken from markets (31.8%; seven of 22) and least from the church (4.0%; one of 25). The highest isolation rate (38.9%) was found in samples from Enugu-Ezike(seven of 23) while the least came from Afikpoand the other locations each with 9.1% isolation rate. This is the first large-scale screening of Cryptococcus neoformans from pigeon droppings in Nigeria. The ecological and epidemiological significance of these findings are discussed.

In Vitro Antifungal Susceptibility of Environmental Isolates of <i>Cryptococcus</i> spp. from the West Region of Cameroon

“…This result confirms the presence of this yeast in the environment, in the west region of Cameroon. Similar studies carried out in Nigeria and Jordan showed prevalences of 22.0% (39/177) and 33.3% (336/1009) respectively (16,17). However, in the above studies, the authors used only pigeon dropping and materials under canopies of eucalyptus trees for isolation, not bat guanos.…”

Epidemiology of Cryptococcus and cryptococcosis in Western Africa

“…The overall isolation rate (22.0%) obtained in this study was higher compared to the single report from Awka and Jos who reported isolation rates of 14.4% and 13%, respectively. 89,95 Though, Awka was part of the study location in the study by Nweze et al, 38 the isolation rate (14.2%) obtained by Mbata 95 was still lower than the overall prevalence of 22.0%reported by Nweze et al 38 It is important to note that these studies are about 13 years apart.…”

“…24 the prevalence of CM in the population was 2.6% with 33% mortality. 30 Then there were increased meningitis cases in HIV patients in Abidjan; hence, Ouattara et al 31 38 Kenya-10%, 39,40 Tunisia-10.4%, 34 Egypt-18% 41 and Libya-34%. 42 The clinical strains isolated were C neoformans (A, AFLP1/VNI), C neoformans × Cryptococcus deneoformans hybrids (AD, AFLP3/VNIII) and Cryptococcus deuterogattii (B, AFLP6/VGII) the only genotype found so far in Africa.…”

Environmental Factors That Contribute to the Maintenance of Cryptococcus neoformans Pathogenesis

“…Following the successful crossing of the blood-brain barrier (BBB), the fungal cells hinder the brain's ability to reabsorb cerebrospinal fluid (CSF), consequently causing an inflammatory condition called meningoencephalitis [19]. This condition is often fatal in immunocompromised cases and is also regarded as an acquired immunodeficiency syndrome (AIDS)-defining illness [20]. Thus, it is not surprising to document high mortality rates due to CNS cryptococcal infection among people infected with HIV [21].…”