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DEFINITION of vector borneA biological association between an arthropod (insect or arachnid ) and a pathogen acquired by feeding on the blood of the infected vertebrate host
OverviewOn the basis of host we can classify vector borne disease in following class;
1) Mosquitoes borne2)Flies borne3)Lice borne 4)Fleas borne5)tick borne
Disease Causative agents
Vectors Methods of infections
Malaria (commonest)
Plasmodium Anopheles mosquitoes
Bite
Dengue fever Virus Aedes mosquitoes
Bite
Encephalitis Virus Culex mosquitoes
Bite
African sleeping sickness
trypnosomas Tse tse fly Bite
Dysentry (amoebic)
Protozoan Housefly Contamination of food
Dysentery (bacilary)
Bacteriumshigella sp.
Housefly Contamination of food
Cholera Vibrio cholerae Housefly Contamination of food
Vectors and Vector borne disease
Disease Causative agents
Vector Method of infection
Onchocerclosis Parasite worm,onchocerco volvulus
Black flies Bite
Plague Bacterium,pastaurella pestis
Oriental rat flies and other fleas
Bites of contact with infected rodents
Rocky mountain fever
Ricketsia American dog tick
Bite
Typhoid Salmonella typhi
Houseflies Contamination of food
Typhus Ricketsia prowzeki
Human louse flies
Contamination or bite
Yellow fever Viruses Aedes mosquitoes
bite
MOSQUITOES & KEY VBDS Responsible for a great VBD burdens
-Malaria-Parasite-Yelow fever-Virus-Dengue fever/hemorrhagic fever-virus-Other viral fevers West Nile, Rift Valley-Filiariasis-Helminth-Encephalitis-viruses
MALARIA; Causative agent:- a) plasmodium vivax
b) plasmodium falciparumc) plasmodium ovaled) plasmodium malarie
Primary host:man Secondary host: anopheles mosquito
Most prevallent in south african countries, and tarai region of Nepal
Controll measure:1) control of host a)clean the surrounding
b)fishes gambusia 2) mosquito net 3) mosquito coils and other mosquito
repellants
FILARIASIS
Causative agent: Waucheria bancroftiHost: 1)primary host: 2)secondary host:
INFECTIVE STAGE:
FLIES & VBDS
African sleeping sickness- african trypnosome parasite- tsetse fly bite
Enteric bacteria diseases-housefly- food contamination
-vibrio cholerae(cholera), typhoid fever(salmonella typhi),shigella sp.(Bacterial dysentery)
Onchoceriasis (river blindness)- helminth- black fly bite
LICE & VBDS-TYPHUS FEVER Agent: ricketssia prowazeckii vector:body licePediculus humanus corporis Associated with poor sanitation and lice
infestation(ectoparasite cariage) -Transmitted by louse feces penetratingskin or inhaled
in dust Controlled with insectidial body powder and
improved sanitation Other louse borne diseases-Trench fever- Bartonella quintana-Relapsing fever-borrelia recurrentensis
TRENCH FEVER Caused by: Bartonella quintana Used in world war I Transmitted by Pediculus humanus(Louse)
FLEAS & VBDS – PLAGUE Plague-pastaurella(now Yersinia) pestis(Gr. –ve bacterium) Fleas carried on rats and other rodents
-Zoonosis-Rats bitten by fleas become infected and dies-Rats then hop onto Humans , biting (taking a blood meal) and infecting with P.pestis
Bubonic plague:flea bite-infection- lymph node-swelling called buboes-septicemia-fever bubonic plague-dark patches on skin-called “black death”
Pneumonc plague;secondary spread to lungs can result in pneumonia and ability to spread via respiratory secretion and droplets, resulting in person to person spread as “pneumonic plague”
Concern as a bioterroism agent
YERSINA PESTIS Caused by gram –ve, non sporing,non
motile,short coccobacillus pasturella pestis Plaque Host: Rattus rattus (Rats)
Treatment: antibiotics like aminoglycosides,chloramphenicol,co-trimoxazole,tetracyclin.
CONTROL: Control of the vector:
1)rats can be killed by rat poisons2)Fleas by the libral application of insectisides to run rat3)Construction of rat proof dwelling houses4)fumigation of ships and aircrafts
TICKS & VBDS Rocky mountain spotted fever- Rickettsia-tick bite
-causes systemic infection with fever, nausea,vomiting,muscle pain,lack of appetite,severe headache;later ;rash,abdominal pain,joint pain,diarrhea
Lyme disease-spirochete bacterium- Borrelia burgdorferi-tick bite leads systemic disease with fever,headache,fatigue and a characteristic skin rashn called “Erythema migrans”-Untreated, infection can spread to joints,the heart and the nervous system; Neurological sequelae
Erlichiosis-Ehrlichis chaffeenis- a bacterium-Infection causes systemic illness with fever,headache,fatigue and muscle aches-also nausea,vomitting,cough,joint pains, confusion and ocassionally rash.
Q fever :coxiella burnetti-zoonotic
REFRENCES Journals Internet
- www.cdc.gov- www.who.int
library