Intracellular pathogens with widespread drug-resistance contribute substantially to the increasing rates in morbidity and mortality due to emerging and reemerging diseases. Thus, the development of new drugs, including those that can enhance the immune response, is urgently needed. The immunomodulator, P-MAPA, a proteinaceous aggregate of ammonium and magnesium phospholinoleate-palmitoleate anhydride derived from Aspergillus oryzae, have been shown to induce antitumor activities. The ability of this compound to elicit protective immunity against viral infections has not been fully explored. Here, we report findings on the use of P-MAPA as an antiviral agent in a mouse model of acute phleboviral (Punta Toro virus) disease. A dose administered i.p. 24h post-infectious challenge (100mg/kg dose of P-MAPA) was remarkably effective at preventing death due to Punta Toro virus infection. This dose also reduced systemic viral burden and liver discoloration assayed on day 3 of infection. Taken together, our findings indicate that non-specific immunotherapy with P-MAPA appears to be an effective treatment for blocking Punta Toro virus-induced disease and suggest that further exploration with other viral disease models is warranted.