The polluted waters of Nairobi rivers may be turning city men, boys, and pigs impotent, suggests several studies from the University of Nairobi.
The studies show that many mature male pigs (boars) feeding from the rivers in Dandora, Mathare, and Kibera have developed abnormal testicles.
They also show that in many piglets testicles are not descending into the scrotum, a problem researchers blame on their sewer-drinking mothers.
The studies further prove that the rivers carry chemicals known to cause infertility in men and males in other animals. The same chemicals have also been linked to the development of ovarian and breast cancers in women and prostate in men.
Putting this evidence together, the researchers suggest that men and boys may be facing a similar fate with the boars and male piglets in Nairobi.
The studies led by Prof Henry Mutembei and Dr Ambrose Kipyegon Ng'eno of University of Nairobi, suggests that food produced using water from polluted rivers, including kales, could also be hurting fertility in men.
"We are proposing a major study to establish the effects of these chemicals on human food, including vegetables, milk, meat, and eggs," Mutembei told The Standard.
They will look into the link between the chemicals and the possible development of breast and ovarian cancers in women and prostate cancer in males.
"We started investigating the issue following complaints by pig farmers in Nairobi that too many of their male piglets had retained testicles," explained Mutembei.
The farmers, who had complained to the university's Faculty of Veterinary Medicine, had suspected the culprit to be the polluted waters of Nairobi's rivers from which the mothers fed.
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"We investigated and found 10 per cent of male piglets in the areas of Dandora, Mathare, and Kibera indeed had retained testicles," says Mutembei. A pig with two undescended testicles will be infertile.
Next the team moved to investigate whether mature pigs or boars had any problems with their reproductive organs.
In their study, which was published in the International Journal of Veterinary Science in April, the team harvested testicles from a number of boars feeding in the polluted waters of Nairobi rivers. They also collected testicles from boars fed on unpolluted waters as a control.
Examination of the testicular tissue showed abnormalities exclusive to the boars fed on polluted Nairobi waters.
This information, the study says, is important for humans because the domestic pig has over 80 per cent genetic similarity to man.
But to get an even clearer picture, Mutembei says they had further done similar tests on mice.
The researchers fed mice on the contaminated waters of Nairobi River. On examining their testicles, they found similar deformities to those found in the boars.