Antistreptolysin Titers in Cases of Filariasis with Recurrent Lymphangitis among Military Personnel.

Since the outbreak of the war, thousands of military personnel have been stationed in islands of the South Pacific where a non-periodic type of Bancroftian filariasis is prevalent among the native populations, and large numbers of the troops, who have been intensively exposed to the bites of infected mosquitoes, have developed clinical manifestations of filariasis. The pattern of the disease in these men is similar to that described many years ago (1) in Europeans, a few months after their arrival in these same island groups, and consists primarily of a lymphadenitis and remittent lymphangitis, sometimes associated with constitutional symptoms of low-grade fever, chills, malaise, and nausea. The natives are well acquainted with this syndrome and call it "mumu." The chief manifestations of "mumu," as seen among the troops, are lymphadenopathy of the axillary, inguinal, and epitrochlear nodes, with recurrent attacks of a retrograde or centrifugal lymphangitis, and the appearance of evanescent red, swollen, pruritic areas on the affected trunk or extremities (2, 3). The spermatic cord and scrotal contents are frequently affected, the commonest lesion being a funiculitis, with or without epididymitis, orchitis, or hydrocele (4). In the majority of cases, a definitive diagnosis of filariasis cannot be made, since microfilariae have thus far been found but rarely in the blood (3, 5); but the adult parasites have been recovered from involved lymph nodes in a number of patients (6, 7), and skin tests with filarial antigens have yielded positive results in about 85 per cent of the men with clinical evidence of the disease (2, 3, 6, 8). The mechanism which excites the attacks of lymphangitis and fugitive swellings in these cases is of great interest. The aforementioned observers are in general agreement that the chief factor is a sensitization of the host to antigenic substances elaborated by the adult parasites, and that the symptoms are the result of an immune or allergic type of reaction. This opinion is supported by the high incidence of positive skin tests, precipitin tests, and complement fixation reactions with filarial antigens among supposedly infected troops (2, 3, 6, 8), indicating that the majority have developed antibodies to the parasite; by the microscopic appearance of the tissue changes in biopsy specimens (6, 7); and by the fact that the local reactions occurring spontaneously in these naturally infected individuals may be reproduced in many of them following the intradermal inoculation of filarial antigens (2). Another possible mechanism for the recurrent lymphangitis is secondary bacterial infection, since it is well-known from earlier work (9) that lymph stasis and lymph edema predispose to bacterial invasion, particularly with hemolytic streptococci. Furthermore, the so-called "tropical lymphangitis" of the Caribbean area, which clinically resembles the lymphangitis of "mumu" in some respects, has been definitely shown by bacteriological and serological procedures frequently to be initiated by streptococcal infections (10). The infectious etiology of the lymphangitis seen in the cases of filariasis among military personnel has been investigated, using ordinary bacteriological procedures, and thus far cultures have failed to reveal hemolytic streptococci (6, 7). Cultural methods alone may, however, be inadequate, as was clearly demonstrated in cases of tropical lymphangitis (11), in which it was found to be difficult to isolate streptococci at the time of the attacks. It was shown, nevertheless, that the attacks were engendered by a streptococcal infection, since the majority of these cases subsequently showed an immune response characterized by an augmented titer of antistreptolysin "O" in the blood.