E.T.W. Bowen

Viral haemorrhagic fever in southern Sudan and northern Zaire. Preliminary studies on the aetiological agent.

A method and an apparatus for producing openings in sheet metal material being provided in band form as well as a perforated sheet material produced by said method. The method comprises providing notches in the sheet material and stretching partial areas of the notched sheet material by a thickness-reducing processing step, whereby the notches which lie between the stretched partial areas of the notched sheet material are enlarged to form openings. The apparatus for producing openings in sheet metal material comprises roller means for producing notches in the sheet material and roller means for stretching partial areas of the notched sheet material by thickness reduction. The resulting perforated sheet metal material combines the advantages of punched sheet metal, i.e., mechanical stability, and expanded metal mesh, i.e., no loss of material during production of the openings in the sheet material.

FATAL HUMAN DISEASE FROM VERVET MONKEYS

Abstract About thirty cases of acute illness, with 7 deaths, presented in laboratory workers handling tissues from vervet monkeys imported from East Africa. Both blood and tissues from these patients proved infective to guineapigs and the agent has been maintained in nine serial passages in these animals. The most striking pathological changes were found in guineapig livers where intracytoplasmic bodies resembling rickettsias or psittacosis-lymphogranuloma-group viruses were invariably present. These bodies stained purple-red with Giemsa and red with Machiavello stains.

Ebola haemorrhagic fever: experimental infection of monkeys.

Experimental infection of rhesus and vervet monkeys with Ebola virus produced a uniformly fatal illness. The course of the disease resembled that found in man with weight loss, anorexia, fever, haemorrhages and skin rash being frequently seen. Viraemia was obvious within two days of infection and persisted until death which occurred between days five and eight. Virus was found in high concentrations in several organs but particularly in the liver, spleen, and lungs.

Arbovirus infections in Sarawak, October 1968-February 1970.Tembusu and Sindbis virus isolations from mosquitoes.

Thirty isolations of Tembusu virus and four of Sindbis virus were obtained from approximately 280 000 mosquitoes collected between October 1968 and February 1970 in Sarawak, particularly from K. Tijirak, a Land Dyak village 19 miles South of Kuching. Twenty-two isolations of Tembusu virus and two of Sindbis virus were from Culex tritaeniorhynchus; two of Tembusu virus and two of Sindbis virus came from Culex gelidus. Tembusu virus was active throughout the year at K. Tijirak, the highest infection rates in C. tritaeniorhynchus being in January-March and May-August, when the C. tritaeniorhynchus population was declining and ageing. These results confirm that C. tritaeniorhynchus is the principal arthopod host of Tembusu virus in Sarawak. Antibody studies suggest that birds, particularly domestic fowl, are probably vertebrate maintenance hosts of Tembusu and Sindbis viruses in Sarawak.

Arbovirus infections in Sarawak: the role of the domestic pig

The possible role of pigs as arbovirus maintenance hosts and their importance as amplifier hosts was studied. Blood samples from 464 pigs of all ages collected in 1962 and 1964 were tested against 10 arboviruses. Antibodies to Japanese encephalitis and Getah viruses were particularly prevalent and their calculated monthly infection rates were 19-5% and 13-3% respectively. In 1969, 447 pigs were bled monthly throughout the year and the infection rates for Japanese encephalitis virus were calculated in pigs during the first year of life. Infection rates were not uniform throughout the year; the rate increases as the pig grew older and there was a marked seasonal increase in the infection rate in the period from November to January. This coincided with the seasonal major population peak of Culex tritaeniorhynchus following intense breeding of this mosquito prior to rice planting. It is suggested that, in Sarawak, the pig acts as a maintenance host of Japanese encephalitis in a cycle involving C. gelidus mosquitoes and also acts as an important amplifier host towards the end of the year in a cycle involving C. tritaeniorhynchus. It is further suggested that Getah virus is maintained in a similar cycle between C. tritaeniorhynchus and pigs.

Arbovirus infections in Sarawak, October 1968–February 1970: Human serological studies in a Land Dyak Village

449 human sera collected in a Land Dyak village were tested for antibodies to 11 arboviruses. Japanese encephalitis and dengue virus antibodies were particularly prevalent. The rates of infection with these viruses were estimated to be 5-2% per annum for Japanese encephalitis, 8-8% for dengue 1 and 4-3% for dengue 2. Chikungunya virus antibodies were quite common with an annual infection rate of the order of 5% per annum. Infections with other Group A and B and Bunyamwera group viruses were generally at a low level.

Arbovirus isolations from, and serological studies on, wild and domestic vertebrates from Kano Plain, Kenya

Arbovirus infection and presence of haemagglutination-inhibiting antibodies in small mammals, birds and livestock were examined over a period of five years on the Kano Plain in western Kenya. Eleven isolations were made from mammals and birds. The viruses were identified as Arumowot and Germiston while three different agents could not be shown to be related to 188 African arboviruses. Prevalence of antibodies against arboviruses suspected of occurring in the area was generally low.

Arbovirus infections in Sarawak, October 1968-February 1970: GETAH virus isolations from mosquitoes.

14 strains of Getah virus were isolated from a variety of mosquito species collected in Sarawak between October 1968 and February 1970. Ten strains were isolated from C. tritaeniorhynchus 7 of them at K. Tijirak. Single strains were isolated from C. gelidus, C. pseudovishnui, M. bonneae/dives and Aanopheles species. 6 of the isolates were obtained in October 1968 when Japanese encephalitis, Tembusu and Sindbis viruses were also very active. The available evidence suggest that Getah virus in Sarawak is maintained in a cycle similar to that of Japanese encephalitis virus and involves C. tritaeniorhynchus, C. gelidus and domestic pigs.

Congo/Crimean haemorrhagic fever virus from Iraq 1979: I. Morphology in BHK21 cells.

SummaryCongo-Crimean Haemorrhagic Fever virus, isolated from a patient in Iraq, was grown, after passage in suckling mouse brain, in BHK cells. The particles matured after 8–9 days in these cells by budding, usually singly, into cytoplasmic vacuoles throughout the host cells. The virions had an overall diameter of 115 to 125 nm, including rounded surface spikes 15 nm long and 10 nm wide. The viral cores, surrounded by a lipid unit membrane, contained discrete electron-dense elements. It is suggested that the spikes, dimpled at their outer end and possibly hollow throughout their length, passed out through “pores” in the unit membrane.

Arbovirus infections in Sarawak: serological studies in man.

Abstract 1. 1.2,118 human sera collected from all age groups in a wide variety of ecological zones in Sarawak during December 1962 and January 1963, April-May 1964 and September-December 1966, were tested for haemagglutination-inhibiting and neutralizing antibodies to 9 arboviruses. 2. 2.Japanese encephalitis and dengue virus antibodies were prevalent in all areas. The estimated annual infection rate with Japanese encephalitis virus varied from about 2% to over 9% with a mean of 6%. Estimated dengue virus infection rates varied from less than 1 % to over 11% with a mean of just over 5% per annum. 3. 3.There was only slight evidence of infection with group A, Bunyamwera and other group B arboviruses. 4. 4.No significant differences in the prevalence of arbovirus infections could be distinguished between any of the ecological zones. The wide distribution of Japanese encephalitis and dengue virus infections matched the distribution of the principal arthropod hosts of the viruses, C. tritaeniorhynchus, C. gelidus and Ae. albopictus . 5. 5.The general trend of arbovirus infections in Sarawak was of highest infection rates in coastal, estuarine and inland forest areas. Urban areas had the lowest rates while rural areas of settled cultivation had intermediate rates of infection.