Cryptosporidium and Giardia in Africa: current and future challenges

Abstract

Cryptosporidium and Giardia are important causes of diarrhoeal illness. Adequate knowledge of the molecular diversity and geographical distribution of these parasites and the environmental and climatic variables that influence their prevalence is important for effective control of infection in at-risk populations, yet relatively little is known about the epidemiology of these parasites in Africa. Cryptosporidium is associated with moderate to severe diarrhoea and increased mortality in African countries and both parasites negatively affect child growth and development. Malnutrition and HIV status are also important contributors to the prevalence of Cryptosporidium and Giardia in African countries. Molecular typing of both parasites in humans, domestic animals and wildlife to date indicates a complex picture of both anthroponotic, zoonotic and spill-back transmission cycles that requires further investigation. For Cryptosporidium, the only available drug (nitazoxanide) is ineffective in HIV and malnourished individuals and therefore more effective drugs are a high priority. Several classes of drugs with good efficacy exist for Giardia, but dosing regimens are suboptimal and emerging resistance threatens clinical utility. Climate change and population growth are also predicted to increase both malnutrition and the prevalence of these parasites in water sources. Dedicated and co-ordinated commitments from African governments involving “One Health” initiatives with multidisciplinary teams of veterinarians, medical workers, relevant government authorities, and public health specialists working together are essential to control and prevent the burden of disease caused by these parasites.

Climate Change and Water-Related Infectious Diseases

“…However, the infection is common, and determining any change due to climate may be difficult. Both Giardia and Cryptosporidium are common in developing countries, and include a variety of species and types, and it has been suggested that climate change will increase malnutrition and contamination of water sources [145].…”

Intestinal protozoan infections among children 0-168 months with diarrhea in Mozambique: June 2014 - January 2018

“…Having a developing immune system, being undernourished, and animal contact are risk factors for intestinal parasite infection [2,7,8]. Symptoms of intestinal parasites can include lack of appetite, anemia, abdominal pains, cognitive impairment, fever, vomiting, malabsorption, and diarrhea [2,7,8].…”

Prevalence and Genotype Distribution of Giardia duodenalis in Rabbits in Shandong Province, Eastern China

“…Humans can be infected through ingesting water and food contaminated with G. duodenalis cysts [6]. e clinical symptoms of giardiasis are diarrhea, dehydration, abdominal pain, nausea, vomiting, and weight loss [2,6,7]. Giardiasis caused by G. duodenalis also has been recognized as an important zoonotic disease for both public and animal health [2,7,8].…”