history of epidemiology

8/10/2019 History of Epidemiology

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Credit hours 3(2-1)

BooksVeterinary Epidemiology ; by Thruseld

Epidemiology; by !eon "ordis

#ntrodu$tion to Epidemiology; by %errill


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Dr. Muhammad HassanMushtaq&h''- an*ing +gri$ultural ,niersity'

&'.'China (2//0)

%' $' (ons') ,V+ (2//3)'V'%' CV ,+4' 2///

ational Center o5 E6$ellen$e in %ole$ularBiology (CE%B) &un*ab ,niersity (2//7-

2/1/)Epidemiology and &ubli$ ealth ,V+ (2/1/-

$urrent)


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Epidemiologytudy o5 disease in population8herd

tudy o5 5a$tors that $ause8en$ourage diseasesome diseases are more $ommon in

$ertain geographi$ areas or at di9erenttimes o5 the year or in $ertain type o5animals


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#mportan$e o5 !iesto$k&roides 5ood 5or human$onsumption

The ma*or produ$ts

%ilk and meat

Value +dded produ$tsraught +nimals


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Role of livestock ineconomyLivestock-largest contributorto overall agriculture (53.2!

"re# by $.% in 2&&'%& asagainst 3.5 last year.

)he Fishery sector e*+andedby %.$, against +reviousyear-s gro#th of 2.3.


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co+e of livestock sectorDemand for livestock +roducts isincreasing

/o+ulation gro#th rate and

increased income are the realreasons

0ncrease in red meat +rices clearlyindicate su++ly ga+

)remendous sco+e of e*+ort (risingtrend each year!

)echnology ga+ sho#s sco+e for

increased +roduction


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isease4 disease is an abnormalcondition aecting the body of

an organism. 0t is oftenconstrued to be a medicalcondition associated #ith s+ecic

sym+toms and signs


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0nfectious diseasesResult from microbes1includes viruses, bacteria,fungi, +roto6oa,multicellular +arasites,

and aberrant +roteins(/rions!


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7on infectiousdiseases4lso called non communicablediseases1 not caused by a

+athogen and cannot beshared from one +erson toanother

including most forms ofcancer, heart disease, andgenetic diseases


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History of8+idemiology4 milestone in gro#th of veterinary

medicine #as the establishment of therst +ermanent veterinary school at

9yons, :rance, in %;


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=ntil the last half of the 2&thcentury, em+hasis of veterinary

medicine had been on thetreatment of individual animals.

4+art from routine immuni6ation

and +ro+hylactic treatment ofinternal +arasites, restrictedattention had been given to herdhealth

The development of veterinarymedicine


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Con''>om+rehensive +reventivemedicine, #hich give +ro+er

consideration to bothinfectious and non1infectiousdiseases #as lacking in +ast


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Domestication of

animalsDog #as +robably the rst animal to bedomesticated #hen it became thecom+anion of early hunters.hee+ ? goats1domesticated by '&&&@> in the fertile 7ile valley (basis ofearly +astoral cultures!)he horse +rovided the key tosuccessful e*+loitation of the areanorth of the @lack ea and a 8urasianhorse culture, associated #ith #arriortribes emerged


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Domestication ofanimalsReligious as #ell as aneconomic signicance in early

civili6ations #as basis ofdomestication of animals.

0ndia is the largest cattleculture


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>hanging conce+ts cause of

disease4++roaches to treatment and+revention are the direct

result of theories of cause.Method of treatment used byearly 8gy+tians #as

incantation (belief insu+ernatural s+irits as a+ossible cause of disease!


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%. Demons (8vil+irit!Early man attributed disease tosupernatural po:ers

#n spirit-:orld disease $ould beprodu$ed by :it$hes superhumanentities and spirits o5 the dead

Treatment there5ore in$luded< pla$ation

(stop 5eeling angry) by sa$ri$e; e6or$ism(5or$ible e6pulsion); easion 5or instan$es$attering millet seeds to aoid ampires


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2. Divine #rath4rgued that disease #as

the +roduct of adis+leased su+reme beingA

disease was punishment


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Punishment by god of health and

disease


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3. Meta+hysicalmedicine)he moon, stars ? +lanets#ere considered to aect

health

)reatment frequently

included +articularly foulmedicines and +ractices that+ersisted for many centuries


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$. )he universe ofnatural la#"reeks thought1disease #asthe result of derangement of

four humours of the body:our humours #ere associated#ith four +ro+erties

(heat,moisture, dryness andcold! and #ith four elements(air, earth, #ater and re!


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The unierse o5 naturalla:Diseases #ere considered to becaused by e*ternal forces, includingclimatic and geological changes)he #ord BmalariaB literally meansBbad airB and hints at the %'thcentury belief that the disease #as

caused by stale air.)he "reek idea of disease #assusce+tible to scienticinvestigation


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Miasmatic )heory CfDiseaseMiasmatic theory of

disease1such as cholera#ere caused by a miasma(ancient

"reekA+ollution!, ano*ious form of bad air


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5. >ontagion0dea1diseases can be transmittedfrom one animal to another has its

ubiquitous origins)he Romans believed that diseasecould be s+read by airborne seeds

)he +rimitive Hindus associatedsick rats #ith human +lague, therst suggestion of a zoonosis.


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"erm )heory of Diseases

Main advances1identication ofmicrobes as causes of infectious

diseases (%'th

century!9ouis /asteurBs investigation ofanthra* ? rabies

Robert ochBs discovery of bacteriacausing )@ ? cholera rmlyestablished microbiology (do#nfall1miasmatic theory!


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Microbes as cause of

infection)he set of +ostulates formulated byoch to dene causal agents1used to

identify many microbial diseasessince those early days of bacteriology

Eiruses discovered in late %'thcentury (%F'2! 0#ano#sky

demonstrated that tobacco mosaicdisease could be transmitted by sa+(lterable agent!


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The rst period< until the rst $entury

+0nitial domestication of animalsbrought man into close contact #ith

animals and therefore #ith theirdiseases

Humoral +athology develo+ed andthe miasmatic theory of causeevolved.

laughter became +reventivestrategies


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)he second +eriodA the rst

century 4D until %;


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The third period< 1=>2-

100?The animal plagues espe$ially those o5 $attle

be$ame parti$ularly $ommon in Europe :iththe introdu$tion o5 rinderpest 5rom +sia

&ubli$ $on$ern highlighted by the rinderpestoutbreak o5 10>@ :as responsible 5or theestablishment o5 the British tate Veterinaryeri$e

By the mid-17th $entury disin5e$tion :as alsobeing applied to $ontrol the disease


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The 5ourth period< 100?-

17>/Treatment o5 disease :as based on laboratory

diagnosis inoling isolation o5 agents andidenti$ation o5 lesions 5ollo:ed by Therapy

The dis$oery o5 disease e$tors 5a$ilitatedpreention by e$tor $ontrol


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The 5ourth period< 100?-

17>/Many infectious diseases #ereeither eectively controlled

eradicated using ne#techniques of the microbialrevolution and older techniques

including quarantine,im+ortation restrictions,slaughter and hygiene


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The 5th periodThe animal-health problems and anomalies

stimulated a $hange in attitude to:ardsdisease $ausality and $ontrol


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The 5th periodEeterinary servicesEeterinarians +racticing in the

livestock sector continue tocontrol and treat disease inindividual animals.

Develo+ments in molecularbiology are im+roving diagnostic+rocedures


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7e# control strategies

)#o maIor strategiesA thestructured recording of

information on disease4nalysis of dis. in +o+ulations

urveillance ? monitoringAintensive investigation of+articular diseases


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Recent trendsEeterinary services A >ontrol and treat disease individual

animal 0m+roving diagnostic +rocedures7e# o++ortunities for vaccine +roduction systemsMultication nature of many disease necessitates

modication of the environment of the animal and

management +ractices. :ood animals1reduced levels of +roductionDiseases assessed in terms of subo+timal health,

manifested by decreased herd +erformanceelect suitable J+erformance indicators- (e.g., Jcalving to

conce+tion interval-! herd that miss the targets.

/erformance1related diagnosis.Eeterinarian, involved in husbandry, management and

nutrition. Eeterinarian-s evolving role in animal+roduction.

0nvestigations of s+ecic animal health +roblems ofcom+le* cause, such as mastitis.


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:ood Kuality+rea o5 $on$ern (Vet' publi$ health) is 5ood Auality"uaranteeing :holesomeness o5 5ood at the

abattoir and addresses all leels o5 the

produ$tion $hain'Establishment o5 Auality assuran$e programs on

the 5arm using te$hniAues su$h as +CC&(aard +nalysis Criti$al Control &oints) in 5o$us

5rom Auality $ontrol o5 5ood throughout theprodu$tion'

uantitatie ealuation o5 the risk o5 transmissiono5 in5e$tion throughout the $hain


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4nimal #elfareCbvious as+ects of animal #elfare aredeliberate +hysical abuse (non1accidentalinIury! and neglectL surgical mutilation (tail

docking of dogs!elfare in livestock +roduction systems is

often evaluated in the conte*t of the Jvefreedoms-

freedom from hunger and thirstLfreedom from discomfortL

freedom from +ain, inIury and diseaseL

freedom from fear and distress.


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7ational ? international

disease re+orting#mproed disease reporting systems at the national D

international leel in the preention o5 spread o5 in5e$tiousagents 5orm one $ountry to another'

.esidues need to be identied and eliminated-pesti$ides

and hormones antibioti$ residues4ree internal market in the European ,nion and global

goals to liberalie international trade through the orldTrade Frganiation (TF)highlighting the reAuirement 5or $omprehensie disease

reportingEstablished organiations su$h as the FG$e #nternational

des Epiooties (F#E) are modi5ying their goals andreporting te$hniAues taking a$$ount o5 these ne:reAuirements'


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Herd healthHerd health is a key driver of +rotability in

today-s +roduction environment.Maintaining health is e*tremely challenging,

+articularly as management systems become

more intensive and +rot margins aresquee6ed.Disease robs prots and productivity by

reducing gro#th, increasing deads,light#eights and culls, and adding drug and

vaccine costs.4 healthy and robust immune system +rotects

+rots and animal #elfare by minimi6ing theincidence and eects of disease


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history of epidemiology

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