Malaria is caused by an organism that shifts its shape a lot, so a vaccine is very hard to develop. Malarial merozoite surface proteins, or MSPs, were identified as a viable vaccine for malaria. To mass-produce MSPs, scientists genetically engineered a herd of goats to produce MSPs in their milk. Last year, more goats that produced milk with vaccine were bred in Houston—their purpose is to produce an economic drinkable form of malaria vaccine for third world countries.