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PubMed2004

Is endemic Burkitt's lymphoma an alliance between three infections and a tumour promoter?

Malaria and Epstein-Barr virus (EBV), recognised cofactors for endemic Burkitt's lymphoma, are ubiquitous within the lymphoma belt of Africa, and, unless other cofactors are involved, the tumour should be much more common than it is. Malaria and EBV alone cannot account for the occasional shifting foci and space-time case clusters of endemic Burkitt's lymphoma. Arboviruses and plant tumour promoters are other possible local cofactors that could explain such characteristics. The geographical and age distributions of endemic Burkitt's lymphoma parallel those of potentially oncogenic, mosquito-borne arboviruses. Arboviruses seem to be associated with case clusters of endemic Burkitt's lymphoma, and symptoms compatible with arbovirus infection have been seen immediately before the onset of the tumour. RNA and DNA viruses, including EBV, are promoted by extracts of a commonly used plant, Euphorbia tirucalli, the distribution of which coincides with the boundaries of the lymphoma belt. Extracts of E tirucalli are tumour promoters and can induce the characteristic 8;14 translocation of endemic Burkitt's lymphoma in EBV-infected cell-lines. They also activate latent EBV in infected cells, enhance EBV-mediated cell transformation, and modulate EBV-specific immunity.

Africa↗
PubMed1999

[Fatal fulminating hepatitis due to Herpes simplex virus type 2 in a young immunocompetent female].

Fulminant herpes simplex viral hepatitis is uncommon in immunocompetent subjects. A 24-year-old woman presenting hepatomegaly with fever was hospitalized after returning from a trip to southern Africa. The patient was neither pregnant nor immunocompromised. Because of recent tropical travel, differential diagnosis included alphabetic hepatotropic virus infection, yellow fever, African hemorrhagic fever, and arbovirus infection. After ruling out other common viral etiologies, a definitive diagnosis of herpes simplex viral infection was made on the basis of clinical and laboratory findings showing high fever, leukopenia, and thrombopenia; of histological examination of the native liver after transplantation showing non-inflammatory confluent focal hemorrhagic necrosis; and on serologic tests demonstrating seroconversion for herpes simplex virus type 2. Outcome after transplantation was rapidly fatal but the death was not directly related to infection. The most likely etiology of fulminant hepatitis in a young woman returning from travel in a tropical area is hepatitis virus B or hepatitis virus E in cases involving pregnancy. However herpes simplex virus should be included in differential diagnosis even in immunocompetent subjects.

Adult↗
PubMed2001

The laboratory role in diagnosis of infections transmitted by arthropods.

This article provides an overview of arbovirus diseases from the perspective of laboratory diagnosis and related responsibilities of health personnel. Although the disease manifestations are very diverse, general lessons relevant to optimal use of laboratory resources can be drawn from medically important examples. This approach is warranted, because under conditions of bioterrorism or emergence of a novel pathogen, ecologic clues that ordinarily facilitate identification of an arbovirus infection most likely will be absent.

Animals↗
PubMedDate not supplied

[Improved hemagglutination and hemagglutination inhibition tests for arboviruses].

The capacity of formalinized goose erythrocytes to be agglutinated in interactions with arboviruses was studied. Formalinized goose erythrocytes were found to be as sensitive as native erythrocytes, and were used successfully for diagnosis of arbovirus infections and study of the immune structure of the human population and animals. The superiority of formalinized erythrocytes is determined by the duration of storage (2 years of the observation period) withoug any change in the capacity for agglutination.

Arbovirus Infections↗
PubMed1995

[Tick-transmitted arbovirus in Maghreb].

The problem of arbovirus infections in Maghreb has been relatively neglected in the pst in spite of a rich diversity of biotopes, the presence of potential reservoirs and vectors, and their position on the flight path of the Palearctic-african bird migration systems, western branch. Moreover, West Nile virus has been isolated from southern Algeria since 1968. From 1979 to 1989, ticks were collected from wild birds, pigeons, bats, rodents, poultry, camels, wild boars, domestic mammals and man, and assayed for viruses. On the whole, 424 ticks were virologically studied from Morocco, 582 from Algeria and 601 from Tunisia. Four tick-borne arboviruses have been isolated so far: three from Morocco, Soldado (Nairovirus), Essaouria (Orbivirus) and Kala Iris (Orbivirus) from Ornithodoros (A.) maritimus ticks parasitizing marine birds, and one from Tunisia, Tunis (Phlebovirus), from Argas reflexus hermanni infesting domestic pigeons. Soldado virus may infect man working into colonies of gulls for ornithological or entomological purposes and this infection is associated with a self-limited febrile illness and pruritus. In addition, antibody to Essaouira virus was detected in a wild rodent in Morocco. On the contrary it is unlike that Tunis virus may infect man because A. r. hermanni is a strickly ornithophilic tick. However, Uukuniemi group antibody has been previously evidenced in wild rodents in Tunisia. Finally, it is not excluded that other, more pathogenic, arboviruses such as Congo-Crimean haemorrhagic fever might be accidentally introduced in this sensitive geographical area.

Africa, Northern↗
PubMed1975

A sero-epidemiologic survey on arbovirus in Wuvulu Island.

The authors present here the results of a serological survey on arbovirus infections, which was conducted on 116 out of 505 inhibitants of Wuvulu island, the westernmost island of the Bismarck archipelago, located 260 km north of Wewak, Papua-New Guinea. The islanders are divided in two communities of unequal size: the Wuvulian themselves, who are Micronesians, and the coconut workers who are Melanesians coming from the Sepik district. In addition to the presence of a group A virus, this survey shows a recent infection in the Melanesians by Dengue type 2 virus, probably during the 1971-72 epidemic. The virus did not reach Wuvulu island, as shown by negative results observed in the micronesian sera. A better knowledge of the potential dengue mosquito vectors would be useful in order to define the risk of an eventual introduction of the virus on the remote island.

Arbovirus Infections↗
PubMed1976

Serum dilution neutralization test for California group virus identification and serology.

The serum dilution neutralization test was evaluated for serological diagnosis of California group arbovirus infections and identification of virus isolates. The technical advantages and the degree of subtype specificity of the serum dilution neutralization test over the hemagglutination inhibition test and the complement fixation test were demonstrated with paired specimens from human cases, single human survey sera, and sentinel rabbit sera. Twenty-one virus isolates from various geographical areas of the United States were also used to evaluate the efficacy of the serum dilution neutralization test for specific virus identification.

Adolescent↗
PubMed1979

Seroepidemiologic studies in Oaxaca, Mexico. II. Survey for arbovirus antibody.

A serologic survey was conducted in south-western Mexico to obtain information on human experience with arbovirus infections. Sera were collected from two semitropical areas along the Pacific coast of Oaxaca State, two mountain areas above 1,700 meters and the interior valley at 1,500 meters. Of the 610 sera tested for group A antibody, 4.9 per cent were positive in the hemagglutination-inhibition (HI) test to Venezuelan (VE), 11 per cent to Eastern, and none to Western encephalitis viruses. In neutralization tests the antibody was shown to be probably due to VE virus infections. When sera were screened for group B antibodies in the HI test, 32 per cent were positive with St. Louis encephalitis (SLE), 19 per cent with Ilhéus, and 4 per cent with yellow fever viruses. The pattern of reactions suggested that SLE or an antigenically related virus was responsible for the antibody detected. An unusually high rate was found in a mountain area at 2,000 meters: 41 per cent of 113 persons tested were seropositive to SLE. Of 493 sera screened by complement-fixation test, 6 per cent were positive to Nepuyo, 4 per cent to Patois, and 3 per cent to Tlacotalpan viruses.

Adolescent↗
PubMed1993

Deforestation: effects on vector-borne disease.

This review addresses changes in the ecology of vectors and epidemiology of vector-borne diseases which result from deforestation. Selected examples are considered from viral and parasitic infections (arboviruses, malaria, the leishmaniases, filariases, Chagas Disease and schistosomiasis) where disease patterns have been directly or indirectly influenced by loss of natural tropical forests. A wide range of activities have resulted in deforestation. These include colonisation and settlement, transmigrant programmes, logging, agricultural activities to provide for cash crops, mining, hydropower development and fuelwood collection. Each activity influences the prevalence, incidence and distribution of vector-borne disease. Three main regions are considered--South America, West & Central Africa and South-East Asia. In each, documented changes in vector ecology and behaviour and disease pattern have occurred. Such changes result from human activity at the forest interface and within the forest. They include both deforestation and reafforestation programmes. Deforestation, or activities associated with it, have produced new habitats for Anopheles darlingi mosquitoes and have caused malaria epidemics in South America. The different species complexes in South-East Asia (A. dirus, A. minimus, A. balabacensis) have been affected in different ways by forest clearance with different impacts on malaria incidence. The ability of zoophilic vectors to adapt to human blood as an alternative source of food and to become associated with human dwellings (peridomestic behaviour) have influenced the distribution of the leishmaniases in South America. Certain species of sandflies (Lutzomyia intermedia, Lu. longipalpis, Lu. whitmani), which were originally zoophilic and sylvatic, have adapted to feeding on humans in peridomestic and even periurban situations. The changes in behaviour of reservoir hosts and the ability of pathogens to adapt to new reservoir hosts in the newly-created habitats also influence the patterns of disease. In anthroponotic infections, such as Plasmodium, Onchocerca and Wuchereria, changes in disease patterns and vector ecology may be more difficult to detect. Detailed knowledge of vector species and species complexes is needed in relation to changing climate associated with deforestation. The distributions of the Anopheles gambiae and Simulium damnosum species complexes in West Africa are examples. There have been detailed longitudinal studies of Anopheles gambiae populations in different ecological zones of West Africa. Studies on Simulium damnosum cytoforms (using chromosome identification methods) in the Onchocerciasis Control Programme were necessary to detect changes in distribution of species in relation to changed habitats. These examples underline the need for studies on the taxonomy of medically-important insects in parallel with long-term observations on changing habitats.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMedDate not supplied

[Comparative study of B-lymphocyte activity in the spleen of mice infected with viruses of the tick-borne encephalitis complex].

Most arbovirus infections are characterized by multiplication of the causative agent in tissues of the reticuloendothelial system. In this study, the effect of some viruses of the tick-borne encephalitis complex on the reaction of B-cells of mouse spleens was investigated by the hemolysin-producing activity (number of plaque-forming cells). To equal small doses of a highly virulent (Pan), naturally attenuated (Tp-21) and experimentally attenuated (Tp-21-237) strains the immunocompetent cells of mouse spleens responded by active reactions. The immunocompetence of these cells after primary introduction of the antigens persists and revaccination response occurs after a secondary infection with the same viruses. Under these experimental conditions the active response of spleen cells to the antigenic stimulation correlates with formation of the specific resistance and does not correlate with the level of antihemagglutinins in the blood.

Animals↗
PubMed1976

[Virus diseases of the mouth mucosa].

In accordance with the system of viral species, viral disorders of the oral mucosa may be classified with regard to their intensity of affection. There are but few viral infections exclusively affecting the oral mucosa like e.g. 1. Glossitis papulosa of Michelson, representing a special form of vaccinia inoculata, 2. Gingivo-stomatitis herpetica and 3. warts of the mucosa or condyloma-like papillomas of the oral mucosa including oral papillomatosis, that, itself shows morphological and clinical similarities to laryngeal papilloma. A second group of disorders mainly affecting the oral mucosa includes the "Aphthoid of Pospischill and Feyrter", Zahorsky's herpangina and other viral infections by the Coxsackie group, like vesicular stomatitis. The 3rd group represents viral infections of other organs in which affection of the oral mucosa is a prerogative, e.g. smallpox, varicella, foot-and-mouth disease and pharyngo-conjunctival fever. A 4th group includes those viral infections of the organs in which co-affection of oral mucosa occurs frequently or once in a while (at occasions). Here, we find eczema vaccinatum, herpes zoster, herpes simplex of the oral mucosa mostly on the hard palate, eczema herpeticatum, post-herpetic Erythema exsudativum multiforme, Mononucleosis infectiosa Pfeiffer, viral flu, German measles, parotitis epidemica, rubeola and ECHO-exanthema. A 5th and last group is made up by viral infections of other organs, in which affection of the oral mucosa hardly occurs at all. This group contains paravaccinal Ecthyma contagiosum, poliomyelitis, viral infection of the city of Marburg and some Arbovirus infections. Relatively few viral disorders never co-exist with lesions on the oral mucosa like e.g. Virus-hepatitis or some viral encephalitides. Groups 1 and 2, most important of all, are presented in detail regarding clinics, diagnostics, differential-diagnosis and therapy. The disorders within the other 3 groups are discussed only regarding their importance in the field of ENT-related symptoms of the oral mucosa. A number of pictures and tables completes important clinical details and give further hints to their differential-diagnosis.

Glossitis↗