Dermatophytes and dermatophytosis in the eastern and southern parts of Africa.

Dermatophytosis is currently a disease of global importance and a public health burden. It is caused by dermatophytes, which attack and grow on dead animal keratin. Dermatophytes belong to three genera, namely, Epidermophyton, Microsporum, and Trichophyton. The predominant clinical forms and causative agents vary from one region of the world to another. Poor socioeconomic status, high population densities, and poor sanitary conditions are some of the factors responsible for the high prevalence of dermatophytosis in many developing countries, which include countries in southern and eastern Africa, the focus of this review. To the best of our knowledge, there is currently no review article on published findings on dermatophytosis in the eastern and southern parts of Africa. This information will be of interest to the medical and research community since the world has become a global village. This review covers published research findings in eastern and southern regions of Africa until this date. The countries covered in the current review include Kenya, Ethiopia, Tanzania, South Africa, Mozambique, Madagascar, Malawi, Rwanda, Burundi, Uganda, Zambia, Zimbabwe, and Botswana. T. violaceum is the most common human etiological agent in all the countries under review with prevalence ranging from 56.7% to 95%, except for Madagascar (M. langeronii, reclassified as M. audouinii), Uganda (M. gypseum) and Malawi (M. audouinii). Tinea capitis was the most clinical type, followed by tinea corporis. Etiological agents of animal dermatophytoses were variable in the countries where they were reported. Major risk factors for dermatophytoses are age, climatic, and socioeconomic factors.

Dermatophytosis in northern Africa.

Infections caused by dermatophytes are a global problem and a major public health burden in the world today. In Africa, especially in the northern geographical zone, dermatophytic infections are being reported at an alarming rate. This is mostly because of some local but unique cultural practices, socioeconomic and environmental conditions, lack of reliable diagnostic personnel and facilities and ineffective treatment. Interestingly, the pathogen spectrum and the clinical manifestation are most times different from what is seen in other continents. Several epidemiological studies have been performed on the incidence and aetiology of dermatophytoses in northern Africa. However, there is currently no review article with up-to-date information on the relevant findings reported so far in this region. This information is necessary for clinicians who treat dermatophytic infections all over the world since agents of dermatophytes are no longer restricted because of the rapid mobility of humans from one part of the world to another. Moreover, the epidemiology of dermatophytoses is known to change over time, thus requiring the update of information from time to time. A review of relevant studies published on dermatophytoses in northern Africa is presented. This covers all of old Sudan, Algeria, Egypt, Libya, Tunisia and Morocco.

Epidemiology of tinea capitis among school-age children in Meiganga, Cameroon.

Tinea capitis (TC) commonly called scalp ringworm is a worldwide concern and a public health problem in Africa. This study aimed at determining the epidemiologic profile of TC among school-aged children in the savanna zone of Cameroon. All children present at school during this study period, August 2011-July 2012, were examined for signs suggestive of TC. Children not registered at school were excluded from the study. Pathologic specimens were taken from suspected head lesions and cultured. Amongst the 4601 children, average age 10.7±0.16 years, 377 presented with suggestive TC lesions giving a prevalence of 8.1%. The proportion of boys with TC was (63.7%) higher than in girls (36.3%) (P≤0.05). TC manifestations varied; small plaques of alopecia 59.26% were the most frequent. Communal living was the most incriminated risk factor. Three hundred and thirty six isolates were obtained in culture. The prevalence was significantly higher (P<0.05) in age range between 8 and 12 years, followed by that between 13 and 15. The most prevalent isolate was T. soudannense 56.8%, followed by T. rubrum 29.2%. Only 6.0% of the isolates belonged to the genus Microsporum.

Comparative virulence of Scedosporium species in animal models.

Scedosporium species are an emerging opportunist group of fungi that have been found to cause infections in both immunocompetent and non-immunocompetent individuals. The infections are not regularly distributed among different countries of the world either because of improper identification or other geographical reasons. Strange as it may, disseminated systemic infections have only been reported in some specific countries. We used a mouse model of disseminated infection to assess if strains from Nigeria were virulent and compared it to a few other strains from other countries. S. apiospermum isolated from Nigeria were clearly less virulent than those obtained elsewhere. This may be the reason why this group of fungi has not been associated with specific clinical problems in Nigeria in particular and Africa in general.

In vitro activity of conventional antifungal agents against Scedosporium apiospermum isolates recovered from clinical and environmental samples in Nigeria.

In vitro susceptibilities of Scedosporium apiospermum isolates recovered from clinical and environmental samples in Nigeria were tested against ten conventional antifungal agents, namely: amphotericin B, nystatin, flucytosine, itraconazole, posaconazole, fluconazole, voriconazole, micafungin, ketoconazole, and terbinafine using the CLSI M38-A broth dilution reference method. The isolates showed varied response/sensitivities to the antifungal agents tested. This is probably the first documented testing of Scedosporium apiospermum isolates from Africa in general and Nigeria in particular against a broad range of conventional antifungal agents.

Agar-based disk diffusion assay for susceptibility testing of dermatophytes.

Currently, no agar-based susceptibility testing method has been standardized for testing dermatophytes. We describe a newly developed agar-based method employing disk diffusion assay to test the susceptibility of 47 isolates of dermatophytes against 8 antifungals. Our results show that the method is reproducible, is simple, and could be used to determine the antifungal susceptibility of dermatophytes.

Aetiology of diarrhoea and virulence properties of diarrhoeagenic Escherichia coli among patients and healthy subjects in southeast Nigeria.

Diarrhoeal diseases are one of the most important causes of illness and death all over the world. In Nigeria, the aetiology of diarrhoeagenic bacteria and the virulence of various Escherichia coli pathotypes have not been well-studied because most currently-published data were from the southwestern axis of the country. In total, 520 stool samples were collected from infants, young children, and other age-groups with acute diarrhoeal diseases in Enugu and Onitsha, southeastern Nigeria. Stool samples were collected from 250 apparently-healthy individuals, with similar age distribution and locality, who were considered control subjects. The stool samples were screened for diarrhea-causing bacterial agents. E. coli strains were isolated from both the groups and were examined by polymerase chain reaction (PCR) for 16 virulence genes. Of the 520 stool samples in the diarrhoea group, 119 (44.74%) were E. coli. Fifty (49.02%) were enteropathogenic E. coli (EPEC), 22 (21.57%) were enterotoxigenic E. coli (ETEC) while 7.84% was enteroaggregative E. coli (EAEC). Sex had no effect on the distribution of diarrhoeagenic bacteria, except for EIEC. The E. coli strains isolated from the diarrhoea and healthy asymptomatic age-matched control groups examined by PCR for 16 virulence genes indicate that the detection of EAEC, ETEC, EPEC, and EIEC was significantly associated with diarrhoea (p=0.0002). The study confirmed that several bacterial pathogens, such as E. coli, play an important role in the aetiology of acute diarrhoea in southeastern Nigeria. A routine surveillance, especially for diarrhoeagenic E. coli, would be useful in identifying outbreaks and help identify the potential reservoirs and transmission routes.

Comparative virulence of Scedosporium species in animal models

Scedosporium species are an emerging opportunist group of fungi that have been found to cause infections in both immunocompetent and non-immunocompetent individuals. The infections are not regularly distributed among different countries of the world either because of improper identification or other geographical reasons. Strange as it may, disseminated systemic infections have only been reported in some specific countries. We used a mouse model of disseminated infection to assess if strains from Nigeria were virulent and compared it to a few other strains from other countries. S. apiospermum isolated from Nigeria were clearly less virulent than those obtained elsewhere. This may be the reason why this group of fungi has not been associated with specific clinical problems in Nigeria in pa'rticular and Africa in general.

Isolation and antifungal susceptibility of Exophiala dermatitidis isolates from human stool samples in Nigeria.

We screened a total of 460 stool samples from humans with and without underlying disease for the black yeast and neurotrope, Exophiala dermatitidis using conventional and molecular identification procedures. Sixteen (3.5%) samples were positive. Twelve out of the sixteen positive samples where the fungus was recovered were from individuals who had diarrhoea at the moment of isolation. Two asymptomatic positive cases were within the age bracket of 21-30. Susceptibility testing of the strains using the CLSI M38 protocol suggests that almost all the strains were susceptible to amphotericin B, 5 fluorocytosine, itraconazole, fluconazole and voriconazole. Considering the health risk currently posed by this organism in Asia, especially among healthy younger subjects of the population and the scarcity of data on this fungus in Africa in general and Nigeria in particular, some recommendations were suggested.

Dermatophytosis in Western Africa: a review.

Dermatophytic fungal infections are one of the most common infectious diseases in the world and are among the most commonly diagnosed skin diseases in Africa. They are caused by several dermatophyte species made up of three genera: Trichophyton, Microsporum and Epidermophyton. The pathogen spectrum and the clinical manifestations are totally different from those seen in other continents. The hot and humid environment in Africa is probably the major reason for their high prevalence. In this era of rapid movement from one continent to another and the increasing mobility of humans, agents of dermatophytic infections can no longer be said to be restricted within a given geographical area. This implies that an infection contracted in one part of the world may become manifest in another country where the etiological agent is not normally found. Therefore, updating our knowledge of the geographical distribution of the predominant causative agents of dermatophytosis will provide a better understanding of the risk factors and future epidemiologic trends. This review discusses the clinical signs and manifestations of dermatophytoses and attempts to summarize the current epidemiological trends on dermatomycosis of glabrous skin in Western Africa.

In vitro susceptibility testing of dermatophytes isolated from pediatric cases in Nigeria against five antifungals.

The antifungal activities of itraconazole, ketoconazole, fluconazole, terbinafine and griseofulvin were tested by broth microdilution methods against 71 isolates of dermatophytes isolated from Nigerian children. Most drugs were very active against all the dermatophytes and the MIC 90 ranged from 0.03 to 8.0 microg/mL. This appears to be the first documented data on the antifungal susceptibility testing of isolates of dermatophytes from Nigerian children.

In vitro susceptibility testing of dermatophytes isolated from pediatric cases in Nigeria against five antifungals

The antifungal activities of itraconazole, ketoconazole, fluconazole, terbinafine and griseofulvin were tested by broth microdilution methods against 71 isolates of dermatophytes isolated from Nigerian children. Most drugs were very active against all the dermatophytes and the MIC 90 ranged from 0.03 to 8.0 µg/mL. This appears to be the first documented data on the antifungal susceptibility testing of isolates of dermatophytes from Nigerian children.

Atividades antifúngicas de itraconazole, ketoconazole, fluconazole, terbinafine e griseofulvina foram testadas por métodos de microdiluição em caldo contra 71 isolados de dermatófitos de crianças nigerianas. A maioria das drogas foi muito ativa contra todos os dermatófitos e o MIC 90 variou de 0,03 a 8,0 µg/mL. Estes parecem ser os primeiros dados documentados sobre os testes de susceptibilidade antifúngica de isolados de dermatófitos de crianças nigerianas.

Prevalence of dermatophytic fungal infections in children: a recent study in Anambra state, Nigeria.

We conducted a recent survey of dermatological fungal infections amongst children in both urban and rural parts of Anambra State in the south-east geographical flank of Nigeria during the period January 2003 to December 2003. Samples were collected from 1624 children with clinically suggestive lesions and also between the ages of 4 and 16. Young children aged 7-11 and 4- 6 years had significantly higher incidences (P < 0.05) than their older colleagues aged 12-16 years among samples proved to be mycologically positive by microscopy, culture or both. There was a significant difference in the incidence of dermatophytoses amongst children in urban and rural areas investigated (P < 0.05). Tinea capitis was the predominant clinical type. Trichophyton tonsurans was the most prevalent etiological agent while Microsporum audouinii was the least in occurrence. We compared our result with a recent study in the northern geographical zone and observed that although incidence of dermatophytoses is higher in northern Nigeria, tinea capitis was the predominant clinical type in both regions. In addition, the etiological agents appear to vary from time to time in their occurrence and the reasons for these observations are discussed. A regular surveillance and assessment of the etiologic agent and its prevalence by medical mycologists is strongly recommended to facilitate monitoring, reduce/prevent transmission and spread of dermatophytes in countries like Nigeria where they constitute a public health problem.

Etiology of dermatophytoses amongst children in northeastern Nigeria.

A survey of dermatophytoses was carried out amongst primary school children in Borno State, Nigeria, during February 1997 to January 1998. A total of 2,193 children aged 4-16 years were screened. Out of these, 154 (7.0%) were proved to be mycologically positive by microscopy, culture or both. Incidence was significantly higher (P <0.05) in young children aged 7-11 years (8.1%) and 4-6 years (6.9%) than in older children aged 12-16 years (3.6%). There was a significant difference in the incidence of dermatophytoses amongst children in urban and rural areas (P <0.05). Tinea capitis was the predominant clinical type followed by tinea corporis. Trichophyton schoenleinii was the most prevalent etiological agent (28.1%), followed by T. verrucosum (20.2%) and Microsporum gallinae (18.4%). Other species recovered included T. mentagrophytes (16.7%), T. tonsurans (10.5%), T. yaoundei (4.4%) and M. gypseum (1.8%).