Studies have sought to delineate the sequence of events following Ivermectin treatment that lead to neurologic SAE and sometimes death, while also trying to understand the mechanisms of adverse reactions to develop more appropriate treatments.In a study looking at mass Ivermectin treatment in Cameroon, one of the greatest endemic regions for both onchocerciasis and loiasis, a sequence of events in the clinical manifestation of adverse effects was outlined.It was noted that the patients used in this study had a L. loa microfilarial load of greater than 3,000 per ml of blood.Within 12–24 hours post-Ivermectin treatment (D1), individuals complained of fatigue, anorexia, and headache, joint and lumbar pain—a bent forward walk was characteristic during this initial stage accompanied by fever. Stomach pain and diarrhea were also reported in several individuals.By day 2 (D2), many patients experienced confusion, agitation, dysarthria, mutism and incontinence. Some cases of coma were reported as early as D2. The severity of adverse effects increased with higher microfilarial loads. Hemorrhaging of the eye, particularly the retinal and conjunctiva regions, is another common sign associated with SAE of Ivermectin treatment in patients with L. loa infections and is observed between D2 and D5 post-treatment. This can be visible for up to 5 weeks following treatment and has increased severity with higher microfilarial loads.Haematuria and proteinuria have also been observed following Ivermectin treatment, but this is common when using Ivermectin to treat onchocerciasis. The effect is exacerbated when there are high L. loa microfilarial loads however, and microfilariae can be observed in the urine occasionally.
The only associated symptom in the Peace Corps study was nausea.Researchers believe that geo-mapping of appropriate habitat and human settlement patterns may, with the use of predictor variables such as forest, land cover, rainfall, temperature, and soil type, allow for estimation of Loa loa transmission in the absence of point-of-care diagnostic tests. In addition to geo-mapping and chemoprophylaxis, the same preventative strategies used for malaria should be undertaken to avoid contraction of loiasis. Specifically, DEET-containing insect repellent, permethrin-soaked clothing, and thick, long-sleeved and long-legged clothing ought to be worn to decrease susceptibility to the bite of the mango or deer fly vector. Because the vector is day-biting, mosquito (bed) nets do not increase protection against loiasis.Vector elimination strategies are an interesting consideration. It has been shown that the Chrysops vector has a limited flying range, but vector elimination efforts are not common, likely because the insects bite outdoors and have a diverse, if not long, range, living in the forest and biting in the open, as mentioned in the vector section. No vaccine has been developed for loiasis and there is little report on this possibility. Treatment
Treatment of loiasis involves chemotherapy or, in some cases, surgical removal of adult worms followed by systemic treatment. The current drug of choice for therapy is diethylcarbamazine (DEC), though ivermectin use while not curative (i.e., it will not kill the adult worms) can substantially reduce the microfilarial load. The recommended dosage of DEC is 8–10 mg/kg/d taken three times daily for 21 days per CDC.