D. Carleton Gajdusek

A group of 43 patients from seven families affected by Creutzfeldt-Jakob disease (CJD) with the codon 178Asn mutation of the PRNP amyloid precursor gene is compared to a group of 211 patients with the sporadic form of the disease. As a group, the patients with the codon 178Asn mutation had an earlier age at onset of illness (almost always presenting as an insidious loss of memory), a longer duration of illness, and an absence of periodic electroencephalographic activity. Transmission of disease to primates was accomplished using brain tissue homogenates from 6 of 10 patients, resulting in significantly shorter incubation periods than those due to sporadic CJD inocula. These findings are interpreted and discussed in terms of possible differences in the temporospatial evolution of damage to the brain, and of accelerated induction of polymerized amyloid protein by its mutationally altered template precursor.

Plaque reduction neutralization tests, using five group A arboviruses (chikungunya, Ross River, Getah, Bebaru and Sindbis), were done on sera from human populations in 44 Southeast Asia and Pacific island localities. Specificity of the plaque neutralization test was determined by examining convalescent sera from patients with known alphavirus infections. Chikungunya-specific neutralizing antibodies were demonstrated in sera of persons living in South Vietnam, Northern Malaysia, Indonesia (Kalimantan and Sulawesi), as well as Luzon, Marinduque, Cebu and Mindanao islands in the Philippines. Evidence of Ross River virus infection was found among populations living in West New Guinea and Papua New Guinea mainland, the Bismark Archipelago, Rossel Island and the Solomon Islands. There appeared to be no geographic overlap in the distribution of chikungunya and Ross River viruses, with the separation in their distribution corresponding with Weber's line in the Pacific. Sindbis neutralizing antibodies were found in 7 of 21 populations sampled, but in general the prevalence of infection was low. Four sera, from Vietnam, Malaysia and Mindanao gave monospecific reactions with Getah virus. No evidence of specific Bebaru virus infection was detected. The epidemiology of these five alphaviruses in Southeast Asia and the Pacific islands is discussed.

Two biologically and genetically distinct hantaviruses were isolated from blood and urine specimens collected from four Yugoslavian patients with clinically severe hemorrhagic fever with renal syndrome (HFRS). Viral isolates from three patients, designated strains Belgrade 1-3, were distinct from Hantaan, Seoul, Puumala, and Prospect Hill viruses as determined by plaque-reduction neutralization tests and restriction analysis of enzymatically amplified M-segment fragments. The fourth isolate, called Kraljevo, was indistinguishable from Hantaan virus. Strains Belgrade 1 and 2, like the Kraljevo strain, caused a fatal meningoencephalitis in newborn mice inoculated with 100 pfu of virus intracerebrally and intraperitoneally. Strain Belgrade 3 was much less neurovirulent, requiring 30,000 pfu of virus to cause fatal disease in mice. These data indicate that two distinct hantaviruses, one of which constitutes a new serotype, cause clinically severe HFRS in Yugoslavia.

SummaryAn epidemic of jungle fever which involved almost one-half of 400 Okinawan pioneers who were attempting to settle in the jungle rain-forest of the Bolivian lowlands adjacent to the Brazilian Matto Grosso is described. Fifteen of the cases ended fatally.A new virus, one of the Group A arthropod-borne viruses, serologically related to Semliki Forest virus, has been isolated from the blood of two of the patients. This, the Uruma virus, was responsible for 10 to 15% of the cases of jungle fever; the etiology of the remaining cases remains undetermined. Serological survey of indigenous communities reveals that this virus or a serologically related agent is endemic to the region. The Semliki Forest-Uruma-Mayaro-Chikungunja serological group of agents appears to be a world-circling group of tropical Group A arthropod-borne viruses pathogenic for man.The problem of jungle fever, or pyrexias of unknown origin, in similar attempts of nonindigenous populaces to clear and settle in tropical jungle, and the problem of multiple etiology of any epidemic that develops among them, are discussed.