People who live in rapidly expanding urban areas of low income countries are at the greatest risk of intestinal parasitic infection, according to a new study.
Contact with human and animal fecal matter in areas where safe management of wastewater and fecal waste is lacking causes infections such as hookworms and intestinal protozoa.
The study was conducted by researchers from the Swiss Tropical and Public Health Institute and their colleagues in Uganda. They examined the prevalence and risk factors for intestinal parasitic infections in the growing suburbs of Kampala, where only a small proportion of wastewater is treated.
The vast majority of the city's wastewater is discharged without treatment into open storm water channels, jeopardizing the health of people who come into contact with it.
Dr. Samuel Fuhrimann, the study's lead author, says the findings call for increased protective public health measures for urban farmers and marginalized groups. The study also found that wastewater can be successfully recycled to boost food production.
“The study was conducted within the framework of the Resource Recovery and Reuse project with a clear focus on urban centers in low and middle income countries," said Fuhrimann. "There we had one major recourse, which was wastewater, and this generated a lot of livelihood when it is reused, especially in the urban settings. The high nutrient loads and the all-year-round availability has a lot of gains for agriculture and aquaculture in these settings.”
The study used a cross-sectional survey of five groups totaling about 950 people. The pool included people who would likely be at risk of contact with the wastewater, including workers at wastewater facilities, workers collecting fecal sludge from pits using vacuum trucks, urban farmers and slum dwellers.
While the examination of only one stool sample was used per person, Fuhrimann says the results raise important issues concerning the proper treatment of fecal waste.
“As urbanization continues at a rapid pace, this poses special challenges for the safe management of the wastewater and also fecal sludge, which is actually collected from pit latrines," said Fuhrimann, adding that some 90 percent of Kampalans rely on pit latrines for toilets, causing a huge challenge for safe waste management.
Reducing health risks
Fuhrimann also says the goal now is to reduce the health risks of these people, especially urban farmers who show the highest risk for intestinal parasites from fecal contamination.
“For example, the sanitation workers who were exposed [on a daily basis] have actually the lowest risk and also the lowest prevalence of all worm infections,” said Fuhrimann.
“But at the same time we found that 76 percent of urban farmers were infected with intestinal parasites. So this is what we normally expect in a rural setting, not in an urban setting where we have all the medical healthcare available—and especially for hookworms and schistosoma mansoni, which can both penetrate the skin," he said. "We could also determine that the level of education is one of the major factors which is linked to these infections.”
Fuhrimann stressed the critical importance that urban farmers and other workers who might be exposed to waste matter take the necessary precautions to protect themselves on a daily basis from exposure to human and animal waste. This includes wearing protective clothing and using clean water to wash equipment.
“The washing of all this equipment is very important," he said. "Many of the people there wash the equipment directly with wastewater, which of course re-contaminates the equipment again."
Fuhrimann notes the importance of personal hygiene and emphasizes that handwashing after work is very important. He also notes that open defecation is still occurring at a high rate and people should use toilet facilities whenever possible.
“And last there is also the regular deworming, which is not happening," he said. "We would recommend that farmers deworm themselves every two-three months."
Improved safety, he said, requires all stakeholders to become actively engaged in educating people about the importance of personal hygiene and implementing procedures and guidelines to ensure the proper disposal of waste.
Policymakers, he added, should explore causes of water contamination through, for example, toilets or the illegal discharge of fecal matter.
Fuhrimann also said another important aspect to consider with improper waste disposal is the impact it has on children, who are at the highest risk of contamination and parasitic worms.