596 research outputs found
The pathophysiology of severe falciparum malaria.
No full textBy the end of the 1940s, the clinical and pathological features of severe falciparum malaria had been well described by military physicians and pathologists working in theatres of war where the disease was endemic. From that time serious efforts were made to discover the pathophysiology of the severe manifestations of malaria because an understanding of these mechanisms forms an important basis for the clinical management of affected patients. Recently, after a period of neglect, there has been a revival of interest in malaria as a subject for clinical and laboratory research. In this article, Rodney Phillips and David Warrell review aspects of that work and attempt to unravel the mysteries of the pathophysiology of severe malaria in man
Intracranial pressure in African children with cerebral malaria
No full textOpening lumbar cerebrospinal fluid (CSF) pressure was measured with a paediatric spinal fluid manometer in 26 of 61 Kenyan children (mean age 39 months) with cerebral malaria. In all cases pressure was above normal (mean [SD] 22·6 [7·4] cm CSF, range 10·5-36). Clinical features of our patients suggest that intracranial hypertension is important in the pathogenesis of cerebral malaria in children, especially as a cause of death. We suggest that raised intracranial pressure is secondary to increased cerebral blood volume. Lowering intracranial pressure may significantly reduce the mortality and morbidity of cerebral malaria. The potential risks and benefits of lumbar puncture should be considered carefully in patients with suspected cerebral malaria
Human rabies: a continuing challenge in the tropical world.
No full textMore than 99% of all human rabies deaths in the world occur in tropical developing countries. In India alone, 30,000 to 50,000 people may die of rabies each year. The Lyssaviruses (Family Rhabdoviridae) include rabies and rabies-related viruses, 3 of which have caused human disease. Rabies is a zoonosis, principally affecting domestic and stray dogs in most parts of Africa, Asia and Latin America. In North America, southern Africa, parts of the Caribbean and Europe, the principal mammalian reservoir species are wild carnivores. The pathogenesis, clinical features and differential diagnosis of rabies are discussed. The planning of rabies control strategies requires background information on the distribution and incidence of rabies in animals and the species involved. In some parts of the world, such as Latin American cities, most domestic dogs, even apparent strays, have an owner and can be immunized with conventional canine vaccines during well publicized campaigns. However, in areas such as India, where there may be a high proportion of stray domestic dogs without owners, and in those areas where wild mammals are the principal reservoir species, immunization may be possible using live attenuated or recombinant oral vaccines distributed in baits. In the poor tropical developing countries, unsatisfactory nervous tissue vaccines are still widely used. However, economical multisite intradermal regimens using tissue culture vaccines have proved effective and have begun to replace nervous tissue vaccines in some countries
Rabies and other lyssavirus diseases.
No full textThe full scale of the global burden of human rabies is unknown, owing to inadequate surveillance of this fatal disease. However, the terror of hydrophobia, a cardinal symptom of rabies encephalitis, is suffered by tens of thousands of people each year. The recent discovery of enzootic European bat lyssavirus infection in the UK is indicative of our expanding awareness of the Lyssavirus genus. The main mammalian vector species vary geographically, so the health problems created by the lyssaviruses and their management differ throughout the world. The methods by which these neurotropic viruses hijack neurophysiological mechanisms while evading immune surveillance is beginning to be unravelled by, for example, studies of molecular motor transport systems. Meanwhile, enormous challenges remain in the control of animal rabies and the provision of accessible, appropriate human prophylaxis worldwide
Human rabies: a continuing challenge in the tropical world.
No full textMore than 99% of all human rabies deaths in the world occur in tropical developing countries. In India alone, 30,000 to 50,000 people may die of rabies each year. The Lyssaviruses (Family Rhabdoviridae) include rabies and rabies-related viruses, 3 of which have caused human disease. Rabies is a zoonosis, principally affecting domestic and stray dogs in most parts of Africa, Asia and Latin America. In North America, southern Africa, parts of the Caribbean and Europe, the principal mammalian reservoir species are wild carnivores. The pathogenesis, clinical features and differential diagnosis of rabies are discussed. The planning of rabies control strategies requires background information on the distribution and incidence of rabies in animals and the species involved. In some parts of the world, such as Latin American cities, most domestic dogs, even apparent strays, have an owner and can be immunized with conventional canine vaccines during well publicized campaigns. However, in areas such as India, where there may be a high proportion of stray domestic dogs without owners, and in those areas where wild mammals are the principal reservoir species, immunization may be possible using live attenuated or recombinant oral vaccines distributed in baits. In the poor tropical developing countries, unsatisfactory nervous tissue vaccines are still widely used. However, economical multisite intradermal regimens using tissue culture vaccines have proved effective and have begun to replace nervous tissue vaccines in some countries
Venomous bites, stings, and poisoning: An update
No full textThis article discusses the epidemiology, prevention, clinical features, and treatment of venomous bites by snakes, lizards, and spiders; stings by fish, jellyfish, echinoderms, insects, and scorpions; and poisoning by ingestion of fish, turtles, and shellfish. Invertebrate stings cause fatalities by anaphylaxis, secondary to acquired hypersensitivity (Hymenoptera, such as bees, wasps, and ants; and jellyfish), and by direct envenoming (scorpions, spiders, jellyfish, and echinoderms). Simple preventive techniques, such as wearing protective clothing, using a flashlight at night, and excluding venomous animals from sleeping quarters, are of paramount importance to reduce the risk of venomous bites and stings
Louse-borne relapsing fever (Borrelia recurrentis infection)
No full textLouse-borne relapsing fever (LBRF) is an epidemic disease with a fascinating history from Hippocrates' times, through the 6th century 'Yellow Plague', to epidemics in Ireland, Scotland and England in the 19th century and two large Afro-Middle Eastern pandemics in the 20th century. An endemic focus persists in Ethiopia and adjacent territories in the Horn of Africa. Since 2015, awareness of LBRF in Europe, as a re-emerging disease, has been increased dramatically by the discovery of this infection in dozens of refugees arriving from Africa.The causative spirochaete, Borrelia recurrentis, has a genome so similar to B. duttonii and B. crocidurae (causes of East and West African tick-borne relapsing fever), that they are now regarded as merely ecotypes of a single genomospecies. Transmission is confined to the human body louse Pediculus humanus corporis, and, perhaps, the head louse P. humanus capitis, although the latter has not been proved. Infection is by inoculation of louse coelomic fluid or faeces by scratching. Nosocomial infections are possible from contamination by infected blood. Between blood meals, body lice live in clothing until the host's body temperature rises or falls, when they seek a new abode.The most distinctive feature of LBRF, the relapse phenomenon, is attributable to antigenic variation of borrelial outer-membrane lipoprotein. High fever, rigors, headache, pain and prostration start abruptly, 2-18 days after infection. Petechial rash, epistaxis, jaundice, hepatosplenomegaly and liver dysfunction are common. Severe features include hyperpyrexia, shock, myocarditis causing acute pulmonary oedema, acute respiratory distress syndrome, cerebral or gastrointestinal bleeding, ruptured spleen, hepatic failure, Jarisch-Herxheimer reactions (J-HR) and opportunistic typhoid or other complicating bacterial infections. Pregnant women are at high risk of aborting and perinatal mortality is high.Rapid diagnosis is by microscopy of blood films, but polymerase chain reaction is used increasingly for species diagnosis. Severe falciparum malaria and leptospirosis are urgent differential diagnoses in residents and travellers from appropriate geographical regions.High untreated case-fatality, exceeding 40% in some historic epidemics, can be reduced to less than 5% by antibiotic treatment, but elimination of spirochaetaemia is often accompanied by a severe J-HR.Epidemics are controlled by sterilising clothing to eliminate lice, using pediculicides and by improving personal hygiene
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