History of Discovery: A Timeline
History of Lymphatic Filariasis: 2000BC-500AD
Due to the fact that there is no reliable written record of lymphatic filariasis before the 16th century, ancient historical evidence of lymphatic filariasis cannot be confirmed. Lymphatic filariasis has been known to occur in the Nile region, and ancient artifacts suggest that the disease may have been present as early as 2000BC. A statue of Pharaoh Mentuhotep II depicts swollen limbs, a characteristic of elephantiasis, which is a symptom of heavy lymphatic filariasis infection. Artifacts from the Nok civilization in West Africa may show scrotal swelling, another characteristic of elephantiasis. The Nok artifacts date much later than the Egyptian artifacts, from about 500AD.
The first written account of lymphatic filariasis comes from the ancient Greek and Roman civilizations. In these civilizations, writers were even able to differentiate between the similar symptoms of leprosy and lymphatic filariasis, describing leprosy as "elephantiasis graecorum" and lymphatic filariasis as "elephantiasis arabum."
Discovery of Symptoms: 1588-1592
The first reliable documentation of lymphatic filariasis symptoms did not occur until an exploration of Goa between 1588 and 1592. During this trip, Jan Huygen Linschoten wrote that inhabitants were "all born with one of their legs and one foot from the knee downwards as thick as an elephants leg." Although this was the first account of lymphatic filariasis symptoms, more documentation was made in parts of Africa and Asia soon after.
In 1849, William Prout became the first to document a condition common to lymphatic filariasis called chyluria. This occurs with the passage of lymph in the urine so it appears milky. Such a description was made in Prout's book entitled On the Nature and Treatment of Stomach and Renal Diseases.
Discovery of Microfilariae: 1863 and 1866
In 1863, French surgeon Jean-Nicolas Demarquay became the first to record the observation of microfilariae in fluid extracted from a hydrocoele (another common symptom of lymphatic filariasis). Three years later, Otto Henry Wucherer discovered microfilariae in urine in Brazil. However, the connection between these two discoveries was not made until Timothy Lewis noted the occurrence of microfilariae in both blood and urine. Lewis was also the first to make the association between these microfilariae and elephantiasis.
Discovery of the Adult Worm: 1876
Soon after the discovery of microfilariae, the adult worm was documented by Joseph Bancroft. The observed species was later named after Bancroft, and we now recognize it as W. bancroft.
Discovery of the Life Cycle: 1877
Perhaps the most important discovery related to lymphatic filariasis was that made by Patrick Manson in 1877. Manson was the first to look for an intermediate host for lymphatic filariasis microfilariae. In 1877, he was finally able to pinpoint the microfilariae in mosquitoes. This discovery was later applied to other tropical diseases such as malaria, and was the first discovery of an arthropod as a vector. However, Manson incorrectly hypothesized that the transmission occurred when the mosquito deposited the filaria in water that then infected humans through ingestion of contaminated water or direct skin penetration.
Discovery of Transmission: 1900
In 1900, George Carmichael Low discovered microfilariae in the proboscis of mosquitoes, and finally pinpointed the true mechanism of transmission. Due to this discovery, we now know that transmission is due to an infective bite from a mosquito vector.
As research on lymphatic filariasis continues, more and more discoveries are made in regards to prevalence, treatment options, prevention methods, transmission cycles, and even new species. Clearly, current information on lymphatic filariasis is not complete, and further research is needed.
(Reference 7 is used for all paraphrased information on this page.)