ABSTRACT
BACKGROUND: Kuru is a transmissible spongiform encephalopathy that was identified in Papua New Guinea in the late 1950s. Several thousand cases of the disease occurred during a period of several decades. Epidemiologic investigations implicated ritual endocannibalistic funeral feasts as the likely route through which the infectious agent was spread. METHODS: We estimated the incubation period distribution of kuru using a back-calculation model and explored the relation among sex, age at infection, and incubation period. Key assumptions in the model were that the number of new kuru infections in a year was proportional to the number of kuru cases dying that year, and that the epidemic arose from a single case of sporadic Creutzfeldt-Jakob Disease occurring around 1900. RESULTS: The mean incubation period of kuru was estimated at between 10.3 and 13.2 years. Point estimates of the 90th percentile ranged from 21.1 to 27.0 years. The incubation period in females was estimated to be shorter than that in males. The shortest incubation periods were estimated in adult women, who may have been exposed to the largest doses of infectious material. CONCLUSIONS: Our findings suggest that the relatively young age of cases of variant Creutzfeldt-Jakob disease probably reflects increased levels of exposure in young people, rather than age-dependency in the incubation period.
Subject(s)
Kuru/epidemiology , Adolescent , Adult , Child , Female , Humans , Kuru/mortality , Male , Middle Aged , Models, Statistical , Papua New Guinea/epidemiology , Risk Factors , Time FactorsSubject(s)
Prion Diseases , Adult , Cannibalism , Child , Creutzfeldt-Jakob Syndrome/diagnosis , Creutzfeldt-Jakob Syndrome/mortality , Creutzfeldt-Jakob Syndrome/transmission , Female , Gerstmann-Straussler-Scheinker Disease/diagnosis , Gerstmann-Straussler-Scheinker Disease/mortality , Humans , Iatrogenic Disease , Incidence , Kuru/diagnosis , Kuru/mortality , Kuru/transmission , Male , Middle Aged , Prion Diseases/diagnosis , Prion Diseases/epidemiology , Prion Diseases/mortality , Prion Diseases/prevention & control , Prion Diseases/transmission , Risk Factors , Spain/epidemiology , Time Factors , United Kingdom/epidemiologyABSTRACT
La autoreplicación del prion cumple un papel esencial en la patogenia de este grupo de afecciones caracterizadas por la producción de encefalopatías espongiformes, tanto en los casos determinados por un factor genético hereditario como en los provocados por iatrogenia o posiblemente por la ingestión de alimentos o sustancias contaminadas. En ambos casos la producción de una variante conformacional de la proteína prion plantea incógnitas por su mecanismo de replicación sin la intervención de DNA o RNA. Finalmente la implicancia de la epidemia en el ganado bovino aparecida hace más de 10 años en inglaterra, resulta inquietante a la luz de la nueva variante de este origen comunicada en 1996 en los seres humanos.
Subject(s)
Humans , Animals , Infant, Newborn , Infant , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Cattle , Diffuse Cerebral Sclerosis of Schilder , Prion Diseases/genetics , Prion Diseases/history , Kuru/mortality , Prions/pathogenicity , Creutzfeldt-Jakob Syndrome/complications , Creutzfeldt-Jakob Syndrome/diagnosis , Creutzfeldt-Jakob Syndrome/history , Creutzfeldt-Jakob Syndrome/immunology , Creutzfeldt-Jakob Syndrome/epidemiology , Sleep Initiation and Maintenance Disorders/genetics , Communicable Diseases/complications , DNA Mutational Analysis , Food Chain/standards , Food ContaminationABSTRACT
La autoreplicación del prion cumple un papel esencial en la patogenia de este grupo de afecciones caracterizadas por la producción de encefalopatías espongiformes, tanto en los casos determinados por un factor genético hereditario como en los provocados por iatrogenia o posiblemente por la ingestión de alimentos o sustancias contaminadas. En ambos casos la producción de una variante conformacional de la proteína prion plantea incógnitas por su mecanismo de replicación sin la intervención de DNA o RNA. Finalmente la implicancia de la epidemia en el ganado bovino aparecida hace más de 10 años en inglaterra, resulta inquietante a la luz de la nueva variante de este origen comunicada en 1996 en los seres humanos. (AU)
Subject(s)
Humans , Animals , Infant, Newborn , Infant , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Aged , Cattle , Prion Diseases/genetics , Prion Diseases/history , Creutzfeldt-Jakob Syndrome/history , Creutzfeldt-Jakob Syndrome/epidemiology , Creutzfeldt-Jakob Syndrome/diagnosis , Creutzfeldt-Jakob Syndrome/complications , Creutzfeldt-Jakob Syndrome/immunology , Sleep Initiation and Maintenance Disorders/genetics , Kuru/mortality , Diffuse Cerebral Sclerosis of Schilder , Prions/pathogenicity , Communicable Diseases/complications , DNA Mutational Analysis , Food Chain/standards , Food ContaminationSubject(s)
Slow Virus Diseases/physiopathology , Viruses, Unclassified/physiology , Animals , Creutzfeldt-Jakob Syndrome/physiopathology , Disease Models, Animal , Female , Humans , Kuru/epidemiology , Kuru/mortality , Kuru/physiopathology , Male , Pan troglodytes , Scrapie/physiopathology , Sheep , Slow Virus Diseases/transmission , Virus ReplicationABSTRACT
Theis report discusses problems involved in the diagnosis of kuru. The gentic and epidemiological pattern is also reviewed. This reveals a continuing overall reduction in kuru incidence with the disappearance of juvenile cases and increasing age of male kuru patients a reduction in the age of female cases. The significance of these trends in relation to the transmission of kuru is discussed.
Subject(s)
Kuru/diagnosis , Adolescent , Adult , Child , Disease Outbreaks/epidemiology , Female , Humans , Kuru/epidemiology , Kuru/mortality , Male , Mental Disorders/etiology , New Guinea , Sex Factors , Strabismus/etiology , SuicideABSTRACT
Important changes have occurred in the epidemiology of kuru since the last review in 1970. There has been a continued decline in the annual incidence, particularly in females. There is a change in the average age of onset in both sexes, and cases are no longer seen in children and adolescents. Alteration in the geographical distribution has resulted in kuru now being confined almost wholly to the South Fore region.
Subject(s)
Kuru/epidemiology , Adult , Age Factors , Anthropology, Cultural , Female , Humans , Kuru/mortality , Kuru/transmission , Male , Middle Aged , New Guinea , Sex RatioABSTRACT
The validity of the reported association between GcAb and kuru is analyzed. Phenotypes with one or more GcAb genes have an increased incidence of the disease at the expense of Gc 1-1 and Gc 2-2. Incidence ratios of kuru associated with various phenotypes examined over the linguistic groups studied indicate that only Gc Ab-Ab persons have a significantly greater chance of dying of kuru. The association X2 for the incidence ratio for those phenotypes possessing only one GcAb gene is significant, but there is significant heterogeneity between groups studied. Those of the Gc Ab-Ab phenotype are six times as likely to contract kuru as the baseline group. Criticisms of this analysis include difficulties defining an adequate control group in such heterogeneous populations, errors in determination of Gc phenotypes, inclusion of persons incubating kuru in the control groups, and questions of validity of statistical tests in isolated inbred populations.
