Date Published: March 6, 2015
Publisher: Public Library of Science
Author(s): Daniel Eibach, Ralf Krumkamp, Hassan M. Al-Emran, Nimako Sarpong, Ralf Matthias Hagen, Yaw Adu-Sarkodie, Egbert Tannich, Jürgen May, Genevieve Milon. http://doi.org/10.1371/journal.pntd.0003551
Abstract: BackgroundThe relevance of Cryptosporidium infections for the burden of childhood diarrhoea in endemic settings has been shown in recent years. This study describes Cryptosporidium subtypes among symptomatic and asymptomatic children in rural Ghana to analyse subtype-specific demographic, geographical, seasonal and clinical differences in order to inform appropriate control measures in endemic areas.Methodology/Principal FindingsStool samples were collected from 2232 children below 14 years of age presenting with and without gastrointestinal symptoms at the Agogo Presbyterian Hospital in the rural Ashanti region of Ghana between May 2007 and September 2008. Samples were screened for Cryptosporidium spp. by PCR and isolates were classified into subtypes based on sequence differences in the gp60 gene. Subtype specific frequencies for age, sex, location and season have been determined and associations with disease symptoms have been analysed within a case-control study.Cryptosporidium infections were diagnosed in 116 of 2232 (5.2%) stool samples. Subtyping of 88 isolates revealed IIcA5G3 (n = 26, 29.6%), IbA13G3 (n = 17, 19.3%) and IaA21R3 (n = 12, 13.6%) as the three most frequent subtypes of the two species C. hominis and C. parvum, known to be transmitted anthroponotically. Infections peak at early rainy season with 67.9% and 50.0% of infections during the months April, May and June for 2007 and 2008 respectively. C. hominis infection was mainly associated with diarrhoea (odds ratio [OR] = 2.4; 95% confidence interval [CI]: 1.2–4.9) whereas C. parvum infection was associated with both diarrhoea (OR = 2.6; CI: 1.2–5.8) and vomiting (OR = 3.1; 95% CI: 1.5–6.1).Conclusions/SignificanceCryptosporidiosis is characterized by seasonal anthroponotic transmission of strains typically found in Sub-Saharan Africa. The infection mainly affects young infants, with vomiting and diarrhoea being one of the leading symptoms in C. parvum infection. Combining molecular typing and clinical data provides valuable information for physicians and is able to track sources of infections.
Partial Text: The parasitic protozoa Cryptosporidium spp. attracts attention with large epidemics in industrialized countries while being undiagnosed and neglected in many developing countries [1,2]. Cryptosporidiosis is an opportunistic infection in immune-compromised patients, which may results in severe and life-threatening diarrhoea [3–5]. In immunocompetent hosts the disease is usually self-limited, however it has been shown to induce weight loss, growth stunting, sustained impact on child development and increased case fatality [2,6–8].
Between May 2007 and October 2008 stool samples from 2,322 children were collected. Median age was 33 months (IQR 14–74) and 1,239 (53.4%) were male. In 116 (5.0%) samples Cryptosporidium spp. were detected by PCR.
All identified C. parvum/hominis subtypes from this study have not yet been identified in any animal samples, suggesting a dominating or even exclusive anthroponotic transmission in the rural Ashanti region of Ghana. The human-to-human transmitted C. hominis subtype families Ia, Ib, Id and Ie make up 58.0% of all Cryptosporidium strains found in this study. These four families were also the most commonly seen in children and HIV+ adults in other developing countries such as Peru, Malawi, Madagascar and India [12,24,26,35]. Within the family Ia this study identified eight different subtypes. This subtype diversity of family Ia is a common finding in developing countries . The high heterogeneity shown in the phylogenetic tree, is thought to express intensive and stable anthroponotic cryptosporidium transmission in contrast to the more homogenous subtype distribution in animal samples or from countries with zoonotic transmission [13,20]. Interestingly, the very rare subtype IbA13G3 comprises 19.3% of all Cryptosporidium strains, being the second most frequent detected subtype in this study. So far this subtype has been only encountered in Peru, Nigeria and Cameroon and a west African origin has been assumed by some studies [24,27].