Urgent opportunistic observations: the study of changing, transient and disappearing phenomena of medical interest in disrupted primitive human communities

Kuru Disease: Bridging the Gap Between Prion Biology and Human Health

This article explores the intriguing case of Kuru disease, a rare and fatal prion disease that once afflicted the Fore people of Papua New Guinea. Scientists are still perplexed as to the origins of Kuru because efforts to discover infectious agents like viruses have been ineffective. Initial research revealed similarities between Kuru and scrapie, a neurological disorder that affects sheep, suggesting potential similarities between the two diseases. In further research, experiments in which chimpanzee brain tissue from Kuru patients was implanted led to the development of Kuru-like symptoms in the animals, suggesting a transmissible component to the condition. Furthermore, data collected from epidemiological studies highlights a drop in Kuru transmission, especially after the Fore people stopped engaging in cannibalism, and the disease showed different incubation times that affected persons within particular age groups. Neuropathological tests in the infected brain tissue have found typical intracellular vacuoles, spongiform alterations, and amyloid plaques. According to studies, Kuru susceptibility has been linked genetically to particular PRNP gene variations. Kuru and other prion disorders have few effective treatments currently, underlining the vital need for early identification. Scientists have created sensitive detection techniques to stop the spread of prion diseases and looked into possible inhibitors. Hypochlorous acid, in particular, has shown potential in cleaning processes. Besides making great progress in understanding Kuru, there are still many unresolved issues surrounding its causes, transmission, and management. The terms "kuru disease," "human prion disease," "transmissible spongiform encephalopathies," and "Creutzfeldt-Jakob syndrome" were used to search the studies; papers unrelated to the review article were removed. Eighty-four articles are included in the review text to fully understand the complexities of this puzzling disease and its consequences for prion biology and human health; additional study is essential.

Kuru, the First Human Prion Disease

Kuru, the first human prion disease was transmitted to chimpanzees by D. Carleton Gajdusek (1923–2008). In this review, we summarize the history of this seminal discovery, its anthropological background, epidemiology, clinical picture, neuropathology, and molecular genetics. We provide descriptions of electron microscopy and confocal microscopy of kuru amyloid plaques retrieved from a paraffin-embedded block of an old kuru case, named Kupenota. The discovery of kuru opened new vistas of human medicine and was pivotal in the subsequent transmission of Creutzfeldt–Jakob disease, as well as the relevance that bovine spongiform encephalopathy had for transmission to humans. The transmission of kuru was one of the greatest contributions to biomedical sciences of the 20th century.

The effect of 5α-reductase-2 deficiency on human fertility

A most interesting and intriguing male disorder of sexual differentiation is due to 5α-reductase-2 isoenzyme deficiency. These male infants are born with ambiguous external genitalia due to a deficiency in their ability to catalyze the conversion of T to dihydrotestosterone. Dihydrotestosterone is a potent androgen responsible for differentiation of the urogenital sinus and genital tubercle into the external genitalia, urethra, and prostate. Affected males are born with a clitoral-like phallus, bifid scrotum, hypospadias, blind shallow vaginal pouch from incomplete closure of the urogenital sinus, and a rudimentary prostate. At puberty, the surge in mainly T production prompts virilization, causing most boys to choose gender reassignment to male. Fertility is a challenge for affected men for several reasons. Uncorrected cryptorchidism is associated with low sperm production, and there is evidence of defective transformation of spermatogonia into spermatocytes. The underdeveloped prostate and consequent low semen volumes affect sperm transport. In addition, semen may not liquefy due to a lack of prostate-specific antigen. In the present review, we discuss the 5α-reductase-2 deficiency syndrome and its impact on human fertility.

Kuru: a journey back in time from papua new Guinea to the neanderthals' extinction

Kuru, the first human transmissible spongiform encephalopathy was transmitted to chimpanzees by D. Carleton Gajdusek (1923-2008). In this review, I briefly summarize the history of this seminal discovery along its epidemiology, clinical picture, neuropathology and molecular genetics. The discovery of kuru opened new windows into the realms of human medicine and was instrumental in the later transmission of Creutzfeldt-Jakob disease and Gerstmann-Sträussler-Scheinker disease as well as the relevance that bovine spongiform encephalopathy had for transmission to humans. The transmission of kuru was one of the greatest contributions to biomedical sciences of the 20th century.

Inherited and somatic mitochondrial DNA mutations in Guam amyotrophic lateral sclerosis and parkinsonism-dementia

There is increasing evidence for mitochondrial dysfunction in neurodegenerative disorders, although the exact role of mitochondrial DNA (mtDNA) mutations in this process is unresolved. We investigated inherited and somatic mtDNA substitutions and deletions in Guam amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia (PD). Hypervariable segment 1 sequences of Chamorro mtDNA revealed that the odds ratio of a PD or ALS diagnosis was increased for individuals in the E1 haplogroup while individuals in the E2 haplogroup had decreased odds of an ALS or PD diagnosis. Once the disorders were examined separately, it became evident that PD was responsible for these results. When the entire mitochondrial genome was sequenced for a subset of individuals, the nonsynonymous mutation at nucleotide position 9080, shared by all E2 individuals, resulted in a significantly low odds ratio for a diagnosis of ALS or PD. Private polymorphisms found in transfer and ribosomal RNA regions were found only in ALS and PD patients in the E1 haplogroup. Somatic mtDNA deletions in the entire mtDNA genome were not associated with either ALS or PD. We conclude that mtDNA haplogroup effects may result in mitochondrial dysfunction in Guam PD and reflect Guam population history. Thus it is reasonable to consider Guam ALS and PD as complex disorders with both environmental prerequisites and small genetic effects.

Utility of Scottish morbidity and mortality data for epidemiological studies of motor neuron disease

OBJECTIVES

To determine the accuracy of (1) hospital discharge data and (2) death certificates, coded as motor neuron disease (MND).

DESIGN

Comparison of data from The Scottish Motor Neuron Disease Register (SMNDR) with routinely collected Scottish Hospital In-Patient Statistics (SHIPS) and death certificate coding.

SETTING

Scotland UK.

PATIENTS

1) 379 adults (> 15 years) discharged for the first time from a Scottish hospital in 1989-90 and (2) 281 deaths in the same period assigned to the International Classification of Diseases (ICD)-9, category 335 (MND).

MAIN OUTCOME MEASURES

The sensitivity and positive predictive value of a diagnosis of MND as retrieved by (1) the Information and Statistics Division of the Common Services Agency for the Scottish Health Service for morbidity data and (2) the Registrar General's office for mortality data, using the SMNDR as the 'gold standard'.

RESULTS

(1) Thirty per cent of adult patients identified as having MND by SHIPS did not have this disease and 23% of patients with MND did not appear on SHIPS. The sensitivity of a diagnosis of MND, as retrieved by SHIPS, was 84% and the positive predictive value was 70% overall. Miscoding of patients with pseudobulbar palsy caused by cerebrovascular disease was the major source of false positive error. The incidence of adult onset sporadic MND was over estimated by SHIPS by a factor of 1.6. (2) Mortality data were more accurate, with a false negative rate of 6% and a positive predictive value of 90%.

CONCLUSIONS

Coded hospital discharge data are an inaccurate record of a diagnosis of MND and cannot, in their present form, be used as a reliable measure of disease incidence in Scotland. Greater care is required in the preparation of discharge summaries and coding if these data are to be useful for health care planning and epidemiological research. SHIPS is, however, an important source of information to achieve a complete sample of patients with MND. There is also a problematic false positive rate for mortality data but this source more closely approximates true incidence.

Adult onset motor neuron disease: worldwide mortality, incidence and distribution since 1950

This review examines the commonly held premise that, apart from the Western Pacific forms, motor neuron disease (MND), has a uniform worldwide distribution in space and time; the methodological problems in studies of MND incidence; and directions for future epidemiological research. MND is more common in men at all ages. Age-specific incidence rises steeply into the seventh decade but the incidence in the very elderly is uncertain. A rise in mortality from MND over recent decades has been demonstrated wherever this has been examined and may be real rather than due to improved case ascertainment. Comparison of incidence studies in different places is complicated by non-standardised methods of case ascertainment and diagnosis but there appear to be differences between well studied populations. In developed countries in the northern hemisphere there is a weak positive correlation between standardised, age-specific incidence and distance from the equator. There is now strong evidence for an environmental factor as the cause of the Western Pacific forms of MND. A number of clusters of sporadic MND have been reported from developed countries, but no single agent identified as responsible.

The Scottish Motor Neuron Disease Register: a prospective study of adult onset motor neuron disease in Scotland. Methodology, demography and clinical features of incident cases in 1989

The Scottish Motor Neuron Disease Register (SMNDR) is a prospective, collaborative, population based study of motor neuron disease (MND) in Scotland. The register started in January 1989 with the aim of studying the clinical and epidemiological features of MND by prospectively identifying incident patients. It is based on a system of registration by recruitment from multiple sources, followed by the collection of complete clinical data and follow up, mainly through general practitioners. In this report the register's methodology and the demography and incidence data for the first year of study are presented. One hundred and fourteen newly diagnosed patients were identified in 1989 giving a crude incidence for Scotland of 2.24/100,000/year. Standardised incidence ratios showed a non-significant trend towards lower rates in north eastern regions and island areas.

Emic accounts of a mystery illness: the Groote Eylandt syndrome

The Aboriginal people of Groote Eylandt, in the Northern Territory of Australia, are suffering from an unusual disease complex having neurological, psychiatric and teratological features, which admits no ready explanation. The island people at various times blame it on the spirits, or accuse enemies, or take some responsibility upon themselves. In this paper, 'emic' accounts of the illness (those current among the members of the society) are described in order to compare them with 'etic' accounts of those who study the society from the outside. Since emic views regulate people's behaviours toward illness, it is suggested these views should complement and inform etic views of researchers and therapists. This principle might apply to all mysterious or poorly understood illness.