This family consists of several ALT protein homologs found in nematodes. Lymphatic filariasis is a major tropical disease caused by the mosquito borne nematodes Brugia and Wuchereria. About 120 million people are infected and at risk of lymphatic pathology such as acute lymphangitis and elephantiasis. Expression of alt-1 and alt-2 is initiated midway through development in the mosquito, peaking in the infective larva and declining sharply following entry into the host. ALT-1 and the closely related ALT-2 have been found to be strong candidates for a future vaccine against human filariasis.