This poor dog is infested with mango fly larvae. They seem to squeeze right out. Poor puppy.
Cordylobia anthropophaga, the mango fly, tumbu fly, tumba fly, putzi fly or skin maggot fly is a species of blow-fly common in East and Central Africa. It is a parasite of large mammals (including humans) during its larval stage .C. anthropophaga has been endemic in the subtropics of Africa for more than 135 years and is a common cause of myiasis in humans in the region.
"The mode of infection by the Cayor Worm. Doctors Rodhain and Bequaert conclude, from their observations in the Congo Free State, that Cordylobia anthropophaga (Grunberg) lays its eggs on the ground. The larvae, known generally as Cayor Worms, crawl over the soil until they come in contact with man or a mammal, penetrate the skin and lie in the subcutaneous tissue, causing the formation of tumors. On reaching full growth, the larvae leave the host, fall to the ground, bury themselves and there pupate. This fly is said to be the most common cause of human or animal myiasis in tropical Africa, from Senegal to Natal. In the region of Lower Katanga where these investigations were made, dogs appeared to be the principal hosts, although Cordylobia larvae were found also in guinea-pigs, a monkey and two white men. The larvae are always localized on those parts of the hosts which come in immediate contact with the soil." (Ann. Soc. Entom. de Belgique, Iv, pp. 192–197, 1911) summary translation in Entomological News. 1911 Vol. xxii:467.
To read more about this click here: http://en.wikipedia.org/wiki/Cordylobia_anthropophaga