Which of the following best describes elephantiasis?

Elephantiasis is best described as an obstruction of lymphatic vessels. This condition is often associated with severe swelling of the limbs and other areas of the body due to the accumulation of lymph fluid. It is commonly caused by filarial infections, particularly by parasites such as Wuchereria bancrofti, which can block the normal flow of lymphatic fluid and lead to extensive edema. This blockage results in the thickening of the skin and underlying tissues, which gives the appearance that resembles the skin of an elephant, hence the name "elephantiasis."

In contrast, an increase in blood pressure does not relate to the specific mechanisms of elephantiasis, which is centered on lymphatic obstruction rather than circulatory issues. A viral infection does not encapsulate the primary cause of this condition, as elephantiasis is primarily associated with parasitic infections, not viruses. Lastly, a bone deformity pertains to structural issues with bones, which is unrelated to the lymphatic system complications that define elephantiasis. Thus, the best description of this condition is indeed the obstruction of lymphatic vessels.