Biodegradable Pesticides in Public Health Entomology
195
due in part to simply the sheer number of different arthropod-borne vertebratepathogenic entities and the variety of habitats and life styles of their vectors.
The number of known arboviruses, for example, is nearing 400 (Berge, 1975);
most are transmitted by mosquitoes, but some are transmitted by ticks, Phlebotomus sp. or Culicoides sp. Fortunately, many appear not to be associated
with human disease, but more than 100 have been so associated.
The World Health Organization (WHO) and the United Nations Development Programme (UNDP) recently launched the Special Program for Research
and Training in Tropical Diseases, which is in part an effort to focus top-flight
research attention on six diseases that afflict more than 600 million people
worldwide, especially in tropical regions. Four of the six diseases are arthropodborne: malaria, filariasis, leishmaniasis, and trypanosomiasis. On the surface,
four diseases sounds like a manageable number. The trouble is that this "Tropical
Big Four" is composed of more than a dozen different parasites and literally
scores of different epidemiological entities.
There are four species of human malaria plasmodia and more than 60 species
of Anopheles are efficient vectors. Filariasis includes not only mosquito-borne
Wuchereria and Brugia but also blackfty-transmitted onchocerciasis. Leishmaniasis involves an as yet unsettled number of Leishmania species, and epidemiological and clinical types. All are transmitted by phlebotomine sandfiies, but
some are anthroponoses and some are zooanthroponoses. Trypanosomiasis includes Trypanosoma cruzi, the etiologic agent of Chagas disease in the Western
Hemisphere, transmitted by several species of triatomine bugs, and two species
of human-infecting tsetse-transmitted trypanosomes in Africa. The two African
diseases are of very different epidemiological patterns. In addition, several species of Trypanosoma that devastate livestock will have to be dealt with if the
people of Africa are to be freed of the yoke of the tsetses.
8.3. INSECTICIDES: THE RECENT PAST
Some insight as to where we are today in public health entomology, and
how we got there, may be gained by examining the situation that currently
confronts organized mosquito control units in the United States and workers in
the global malaria program.
8.3.1. Mosquito Control in the United States
Florida and California have been two of the areas of most intense mosquito
control activity in the U.S., and a National Academy of Sciences study (NAS,
1976) draws an interesting comparison between the history of organized control
195
due in part to simply the sheer number of different arthropod-borne vertebratepathogenic entities and the variety of habitats and life styles of their vectors.
The number of known arboviruses, for example, is nearing 400 (Berge, 1975);
most are transmitted by mosquitoes, but some are transmitted by ticks, Phlebotomus sp. or Culicoides sp. Fortunately, many appear not to be associated
with human disease, but more than 100 have been so associated.
The World Health Organization (WHO) and the United Nations Development Programme (UNDP) recently launched the Special Program for Research
and Training in Tropical Diseases, which is in part an effort to focus top-flight
research attention on six diseases that afflict more than 600 million people
worldwide, especially in tropical regions. Four of the six diseases are arthropodborne: malaria, filariasis, leishmaniasis, and trypanosomiasis. On the surface,
four diseases sounds like a manageable number. The trouble is that this "Tropical
Big Four" is composed of more than a dozen different parasites and literally
scores of different epidemiological entities.
There are four species of human malaria plasmodia and more than 60 species
of Anopheles are efficient vectors. Filariasis includes not only mosquito-borne
Wuchereria and Brugia but also blackfty-transmitted onchocerciasis. Leishmaniasis involves an as yet unsettled number of Leishmania species, and epidemiological and clinical types. All are transmitted by phlebotomine sandfiies, but
some are anthroponoses and some are zooanthroponoses. Trypanosomiasis includes Trypanosoma cruzi, the etiologic agent of Chagas disease in the Western
Hemisphere, transmitted by several species of triatomine bugs, and two species
of human-infecting tsetse-transmitted trypanosomes in Africa. The two African
diseases are of very different epidemiological patterns. In addition, several species of Trypanosoma that devastate livestock will have to be dealt with if the
people of Africa are to be freed of the yoke of the tsetses.
8.3. INSECTICIDES: THE RECENT PAST
Some insight as to where we are today in public health entomology, and
how we got there, may be gained by examining the situation that currently
confronts organized mosquito control units in the United States and workers in
the global malaria program.
8.3.1. Mosquito Control in the United States
Florida and California have been two of the areas of most intense mosquito
control activity in the U.S., and a National Academy of Sciences study (NAS,
1976) draws an interesting comparison between the history of organized control