Acute Lymphatic Filariasis Infection in United States Armed Forces Personnel Deployed to the Pacific Area of Operations during World War II Provides Important Lessons for Today

Abstract

The deployment of United States (US) Armed Forces personnel into the central Pacific islands of Samoa and Tonga, which is highly-endemic for lymphatic filariasis (LF), resulted in thousands of cases of the acute form of this disease and greatly reduced their ability to carry out their mission. The major driving factor for the intensity of transmission was the aggressiveness and efficiency of the Aedes species mosquito vectors, especially the day-biting Ae. Polynesiensis. The paper reminds us of the danger that tropical diseases can pose for troops sent into endemic areas and constant and careful surveillance that is required to prevent rapid resurgence of Aedes-transmitted LF in populations, where the LF elimination program has been successful.

A Historical Review of Military Medical Strategies for Fighting Infectious Diseases: From Battlefields to Global Health

“…Lymphatic filariasis is a highly incapacitating mosquito-borne disease, the second most common after malaria among vector-borne diseases [ 408 ]. The vectors may be Anopheline , Culex and Mansonia mosquitoes, which bite at night, whereas in the Pacific, the vector is the Aedes mosquito, which bites during the day [ 409 ]. The etiological agents are three species of nematode parasites, Wuchereria bancrofti , responsible for 90% of cases, Brugia malayi , present in East-Southeast Asia, and Brugia timori , present in the Timor area [ 408 ].…”

“…The adult worms generate microfilariae, which migrate into lymph and blood channels. The disease may be acute or chronic, and its main manifestations are fever, lymphangitis, lymphadenopathy with pain, and in males, scrotal edema of the acute form, whereas the chronic form is highly invalidating with elephantiasis, lymphedema and hydrocele [ 409 ]. Nearly one billion people in tropical areas are at risk of lymphatic filariasis, and it is estimated that approximately 36 million people are incapacitated as a consequence of chronic lymphatic filariasis [ 409 ].…”

“…The disease may be acute or chronic, and its main manifestations are fever, lymphangitis, lymphadenopathy with pain, and in males, scrotal edema of the acute form, whereas the chronic form is highly invalidating with elephantiasis, lymphedema and hydrocele [ 409 ]. Nearly one billion people in tropical areas are at risk of lymphatic filariasis, and it is estimated that approximately 36 million people are incapacitated as a consequence of chronic lymphatic filariasis [ 409 ]. There are three effective drugs, albendazole, ivermectin, and diethylcarbamazine citrate, which may prophylactically be administered to at-risk populations, as recommended by the WHO, with annual mass drug administration (MDA), a strategy that aims to eradicate filariasis [ 410 ].…”

“…Filariasis was an unexpected invisible enemy for the US troops during WWII in the Pacific war theater, with many thousands of hit men, more than 10,000 among Navy and Marine Corps, and an unspecified number of illnesses among the Army troops, with a global amount estimated at 14,000–16,000 men having clinical evidence of infection and some battalions with 70% of their contingent out of service [ 368 , 408 ]. This acute form of lymphatic filariasis showed a trend of spontaneous clinical resolution once the disease was recognized and the patients were moved away from the endemic countries [ 409 ]. The contributions of the US military researchers to the fight against filariasis ranged from diagnosis to treatment, where the evidence that eradication strategy was possible through a safe and effective treatment was provided [ 368 ].…”

Parasites, Zoonoses and War: A Themed Issue in Honor of Emeritus Professor John M. Goldsmid

“…Prof. Wayne Melrose and Prof. Peter Leggat, who describe and discuss the modern implications of the outbreak of lymphatic filariasis (LF) in United States armed forces deployed to the Pacific Islands during World War 2. Not only do these authors provide a comprehensive summary of this outbreak and its long term impact on those affected veterans, they also use it as an example of why care must be taken to avoid resurgences of LF in the many Pacific islands where elimination has recently been achieved [7].…”