Dr Pam de Waal

Senior Lecturer

Current subjects

GTS161  Introductory Genetics
MLB 153  Molecular Cell Biology

Research focus

I am interested in the epidemiology of pathogens. My research is focused on Spirocerca lupi, a nematode parasite which causes spirocercosis in dogs. Spirocerca lupi eggs are ingested by dung beetles where the larvae develop to the infective stage. The beetles are swallowed by transport hosts such as birds, reptiles or amphibians, where they encyst in organs of the intermediate host. The final host is infested with Spirocerca lupi following the consumption of beetles or any other animal containing infective or encysted larvae. Larvae are released in the stomach of the final host where they penetrate the stomach wall to access the arteries. The larvae migrate in the walls of the arteries to the thoracic aorta. If the aorta ruptures due to migration of the worms, sudden death occurs. The disease is usually only diagnosed in live dogs when oesophageal granulomas cause a physical obstruction in the oesophagus of the dog. The granulomas may undergo neoplasia forming oesophageal sarcomas followed by metastasis.

There is currently no registered cure for spirocercosis. A retrospective analysis of patients presented with S. lupi currently underway at Onderstepoort Veterinary Faculty, UP, indicates a substantial increase in the incidence of the disease over the last eight years.

I am interested in the identification of the intermediate hosts of S.lupi in South Africa. Nothing is known about the population and geographic structure of S.lupi in South Africa. This information would provide a means for pet owners to prevent their dogs from becoming infested and provide a means to predict the infective risk present at a given distance from an outbreak of this nematode.