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Biomedical subjects

A B Knudsen

Publications and source records attributed to A B Knudsen.

14 recordsLinked to original sources
PubMed1996

Occurrence and spread in Italy of Aedes albopictus, with implications for its introduction into other parts of Europe.

Aedes albopictus is considered second only to Ae. aegypti in its importance to man as a disease vector of dengue and dengue hemorrhagic fever. The first sighting in 1979 of the vector species in Europe came from Albania; however, it was only when Ae. albopictus was introduced into Italy in 1990, through the importation of used tires, followed by its subsequent spread, that the species was considered as a threat to public health. At the close of 1995, Ae. albopictus infestations have been reported from 10 Italian regions and 19 provinces. The risk for greater distribution of Ae. albopictus in Europe can potentially be projected, based on well-established criteria such as: where the winter monthly mean temperature is 0 degree C, where at least 50 cm of mean annual rainfall occurs, and where the mean summer temperature is approximately 20 degrees C. Those countries where climatic conditions meet such criteria and that may be vulnerable to a potential introduction of Ae. albopictus include Spain, Portugal, Greece, Turkey, France, Albania, and the former Republic of Yugoslavia. The Italian plan of action, established for the surveillance and control of Ae. albopictus, is presented in detail.

Aedes↗
PubMed1995

Global distribution and continuing spread of Aedes albopictus.

Aedes albopictus ranks second only to Ae. aegypti in importance to man as a vector of dengue and dengue haemorrhagic fever (DHF) which viruses place at risk a potential population of 2 billion people living in tropical and sub-tropical regions. Due to its predilection for breeding in a plethora of habitat within urban and suburban environs as well as peri-rural areas it is spreading rapidly where suitable breeding is available. It exhibits strain differences ranging from the cold-hardy to tropic loving, yet despite limited flight range, it has spread beyond the Orient to China, the Pacific, the Indian Ocean islands, the Americas, parts of continental Africa and into southern Europe. This has been done principally by means of transport of eggs in used tyres via rapid air and sea transport. Egg positive used tyres, when shipped, and later rehydrated by rainfall, produce adult mosquitoes within a few days rapidly infesting new areas. Although dengue and other vector-borne arboviral diseases have not been in Europe in epidemic form for many decades, travelers do not infrequently return from dengue endemic areas with dengue and other similar infections. Aedes albopictus is a potential vector of a number of arboviruses and can transmit them in a vertical or transvenereal manner in nature, thereby providing a means for their maintenance and transmission. Where Ae. albopictus newly occurs, the affected populace immediately are aware of a new daytime, nuisance biting mosquito and complaints addressed to local mosquito control authorities increase significantly. The biological characteristics of the mosquito make its spread within Europe highly probable. The paper offers several avenues to be pursued to reduce the global spread of Ae. albopictus, when examined within the context of Europe and the wider world community.

Aedes↗
PubMed1992

Vector-borne disease problems in rapid urbanization: new approaches to vector control.

Owing to population growth, poor levels of hygiene, and increasing urban poverty, the urban environment in many developing countries is rapidly deteriorating. Densely packed housing in shanty towns or slums and inadequate drinking-water supplies, garbage collection services, and surface-water drainage systems combine to create favourable habitats for the proliferation of vectors and reservoirs of communicable diseases. As a consequence, vector-borne diseases such as malaria, lymphatic filariasis and dengue are becoming major public health problems associated with rapid urbanization in many tropical countries. The problems in controlling these diseases and eliminating vectors and pests can be resolved by decision-makers and urban planners by moving away from the concept of "blanket" applications of pesticides towards integrated approaches. Sound environmental management practices and community education and participation form the mainstay of some of the most outstanding successes in this area. On the basis of these examples, it is argued that the municipal authorities need to apply a flexible methodology, which must be based on the possibilities of mobilizing community resources, with minimal reliance on routine pesticidal spraying. In this way, vector control becomes a by-product of human development in the city environment. This is now a true challenge.

Animals↗
PubMed1991

Aedes aegypti infestation characteristics in several Caribbean countries and implications for integrated community-based control.

Periodic larval surveys for Aedes aegypti were conducted in 11 Caribbean countries between 1983 and 1989. On average, there were 24 potential larval habitats per house including 4.9 which held water at the time of examination. Breteau indices for the various islands ranged from 34.7 to 121.6. In descending order of importance, water storage drums, house plants, buckets, used tires and miscellaneous small discarded containers accounted for 84% of all foci. Highest rates of infestation were found in tires (38.4%) and drums (33.8%). For the development of integrated community-based vector control programs, not only should consideration be given to the larval ecology of Ae. aegypti, but also to the sociological significance of the various container habitats and the selection of control strategies most appropriate for their management.

Aedes↗
PubMed1988

Saint Lucia revisited.

The eastern Caribbean island of Saint Lucia is now famous in parasitological history as the setting for a major programme of schistosomiasis control'. Perhaps less well-known are the island's effective control of many intestinal parasites, and elimination of malaria, such that the current patterns of mortality and other demographic indicators now resemble those of industrialized countries. More recently, the island has become the focus for another community-based health programme as the Caribbean region again comes to grips with Aedes aegypti and its recently imported relative, Aedes albopictus, important vectors of yellow fever and dengue viruses (see Box 1).

Journal Article↗
PubMed1986

The significance of the introduction of Aedes albopictus into the southeastern United States with implications for the Caribbean, and perspectives of the Pan American Health Organization.

The introduction and apparent infestation of Aedes albopictus into the Gulf States of Texas and Louisiana in the United States is viewed as the most singular medical entomological happening of this decade in the Americas. The implications for the Caribbean and other countries southward are serious, as the habitat described for this Stegomyia cousin of Ae. aegypti, is amply available in the Windward and Leeward islands of the Antilles. Studies from the Pacific and regions of Southeast Asia indicate that Ae. albopictus competes for the same peridomestic niches as Ae. aegypti and it has been found to be a competent vector of several dengue serotypes. In this presentation, a call is issued to the mosquito control and abatement programs in the Gulf States to take stringent measures to eliminate this new dengue vector before it becomes thoroughly established and spreads to other states as well as into countries of the Americas and into the West Indies.

Aedes↗
PubMed1980

Dengue hemorrhagic fever in Malaysia: the 1973 epidemic.

The first major Malaysian epidemic of dengue hemorrhagic fever with severe manifestations occurred in 1973, with 969 reported cases and 54 deaths. In a detailed study of 138 clinically diagnosed and laboratory confirmed cases at the General Hospital in Kuala Lumpur, hemorrhagic manifestations were observed in 68.7% and shock in 18.1% of the patients. The cases occurred mainly from May to September, largely in urban and suburban areas of the majority of the states in the country. A main focus of infection was Jinjang, a heavily populated outlying district of Kuala Lumpur, where unusually high incidences of morbidity, severe disease and mortality were seen. Severe disease was seen mostly in children under the age of 15 years, although a significant number of adults suffered milder illnesses. The Chinese population was chiefly affected, due to their living in crowded, low-income housing where the vector, Aedes aegypti, occurred in the greatest numbers. All four dengue types were recovered during the epidemic period, although dengue 3 (DEN-3) was incriminated as the major epidemic type. Entomological data revealed high indices of A. aegypti throughout the country and left little doubt that this epidemic was aegypti transmitted. Spraying and fogging operations were carried out in attempts to control vector populations.

Adolescent↗