1
play

1 Chemical Control of Malaria Public Health I: Malaria Protozoan - PDF document

Aug 21, 2022 •434 likes •572 views

What are Pests? Pests Any organism that bothers humans Depends upon severity of interaction in terms of competition, health concerns or annoyance 1 2 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

  1. What are Pests? Pests ● Any organism that bothers humans – Depends upon severity of interaction in terms of competition, health concerns or annoyance 1 2 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Pesticide Use by Sector Pesticide Use by Sector ● Public Health ● Agriculture ● Forestry ● The Home 3 4 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 1 - Pesticides and Public Health Public Health I: Malaria ● Insects play major role in ● Probably the most devastating insect disease transmission transmitted disease in the world ● Mostly Diptera (>8 Families) ● Typically tropical ● Insects may be obligate hosts – e.g. Malaria in mosquitoes ● Insects may be facultative hosts – e.g. W Nile Virus in mosquitoes 5 6 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 15:32 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 1

  2. Chemical Control of Malaria Public Health I: Malaria ● Protozoan of ● Most significant Plasmodium genus intervention was with DDT ● Causes chills, fatigue, – e.g. Island of Sardinia fever • 1942 = 78,000 cases ● Infection of 300-500M/yr • 1951 = 9 cases after DDT ● Death rate 1-10%, – e.g. Ceylon depending on treatment • <1963 = 3M cases and sp. of Plasmodium • >1963 = 17 cases after DDT 7 8 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Banning of DDT Public Health II: Yellow Fever ● Effectiveness of DDT as pesticide is ● An arbovirus (arthropod borne unparalleled virus) – DDT on surface would persist and continue to ● Causes jaundice and infect flies on contact hemorrhagic illness ● After DDT was banned: ● YF not huge problem but still – Ceylon had 17 cases in 1963 endemic in some places • 1968 = 500,000 cases – WHO estimates 200,000 infections/ • 1970 = 2M cases yr with 30,000 deaths ● DDT still used in 3rd world although ● Outbreak in Ethiopia in 1959 alternatives exist (Deltamethrin) killed 15,000 people 9 10 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health III: Trypanosomiasis Public Health II: Yellow Fever ● Sleeping sickness ● Known since 14th Century (Africa) ● Modern equivalent: West Nile Virus ● Up to 50% mortality in some populations ● Although arbovirus lifecycle not tied to vector, treatment best when applied to vector ● Traditional approach: airsprays of chemical insecticide ● Nowadays, most common is larvicide in water ( B.t. ) 11 12 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 2

  3. Public Health IV: Public Health III: Trypanosomiasis The Plague ● Caused by flagellated protozoan parasite of 2 spp. of ● AKA “The Scourge of Man” Trypanosomiasis ● Devastated entire cities and ● Trypanosoma ingested by TseTse some countries Fly ( Glossina sp.) ● 14th C in Central Europe 25M ● Parasite develops in fly and dead (1/4 of population) migrates to saliva glands ● London 1666 = 70,000 deaths ● Infects human at next blood meal ● India and China (1889-1918) = ● Flies hang-out under leaves, 10M deaths therefore airspray not very effective ● Last outbreak occurred <50yrs ● Best control a combination of ago vegetative clearing and pesticides 13 14 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health V: Typhus Fever Public Health IV: The Plague ● Caused by Ricksettia prowazeki and ● Rat disease, caused by bacteria transmitted by common body louse ( Pasteurella pestis ) vectored by rat flea – Pathogen picked up by louse during ( Xenopsylla cheopis ) bloodmeal, develops in gut and released ● Global disease control involves in feces combining rodenticide and insecticides in – Humans infected by breathing dust or ship hulls contact with wounds – In humid conditions, feces are infectious up to several months ● Treatment involves sanitation/hygiene and louse control with pesticides 15 16 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health V: Typhus Fever 2 - Role of Pests in Agriculture ● Associated with humans in crowded, un-sanitary conditions ● Frequent outbreaks in combat ● Three main categories: forces and prisons: “war fever” and “jail fever” – Insects ● WWII 1943: Naples, Italy under – Diseases siege – Weeds – Bomb shelters overcrowded and filthy – Epidemic of typhus was imminent ● Agriculture is largest user of pesticides – Arrival of Allied Forces with DDT was by sector 1st time typhus outbreak had ever been prevented 17 18 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 3

  4. Contribution of Pesticides to Cash Crops Agricultural Use (%) by Sector Actual losses Production without crop Losses prevented by 1960 1970 1980 1990 2000 2010 protection 30.3% crop protection Weeds Herbicides 20 35 41 45 47 46 13.2% Weeds 16.4% Insecticides 37 37 35 28 27 28 Animal 27.6% 42.1% pests Fungicides 40 27 19 20 21 21 15.6% Animal pests 7.1% Diseases All Others 4 6 6 7 7 6 Diseases 13.3% 4.2% US$ 160 billion Market Value 800 2,00 11,600 28,000 38,000 50,000 US$ 244 Attainable production - US$ ($ M US) billion 579 billion 19 20 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 15:32 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Types of Damage Caused by Insects Insects as Agricultural Pests ● Depends largely on morphology of mouthparts ● Estimated that 75% of all animals are ● Chewing insects insects (mostly beetles) – Defoliators, borers, leaf miners, – Not surprising there are so many ecological root feeders interactions with insects ● Sucking insects – Insects are mostly beneficial, small number – Distort plant growth, stippling are pests on leaves, burning of leaves (secretion of toxins) ● May also be vectors of disease 21 22 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Insects as Agricultural Pests ● Insect pests usually cause incremental damage – Calculate EIL and ET to Types of Damage know when to intervene Caused by ● Sometimes infestations Insects occur and cause huge losses very quickly – e.g. locust swarms – e.g. armyworm “marching” across country 23 24 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 4

  5. Effect of Insects on Food Production For example, Apples ( Malus spp.) ● In grain crops, insects may cause a decrease in yield but do not impact harvest ● Important crop in Ontario quality ● Plagued by codling moth (Cydia ● In fruit and vegetable crops, insects may pomonella ) , red-banded leafroller cause yield reduction and affect harvest ( Argyrotaenia velutinana ) and apple maggot quality due to aesthetic expectations ( Rhagoletis pomonella ) 25 26 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment A) Codling Moth A) Codling Moth ● 2 generations/yr. ● Gen 2: adults emerge, mate and lay eggs near ● Gen 1: adults emerge in spring, mate and fruit lay eggs in upper leaves ● Larvae attack fruit as they mature in late summer ● Larvae migrate to fruit and chew inside ● Therefore, 2 phases of damage ● Larvae eat inside fruit, many fruit fall to – Without intervention, losses can be 20-90% ground with insects in development ● Most damage not visible ● They leave apple, find shelter and pupate – Therefore, need to monitor – Pesticides only useful before larvae enter fruit 27 28 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment B) Red-banded Leafroller C) Apple Maggot ● Also 2 generations per year but occurs ● Most destructive pest of apples two weeks before codling moth ● May have 85% loss if not treated ● Early generation feeds mostly on leaves, ● Overwinters as pupae in soil later generation on fruit ● Adults emerge in early summer, mate ● Complicates treatment with pesticides and lay eggs just beneath skin of fruit ● Larvae burrows as they eat, leaving series of trails (railroad worm) 29 30 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 5

Recommend

More recommend