food borne infections organisms do not have to grow in the food before it is eaten: organisms do not...

Food Borne InfectionsFood Borne Infections

Organisms do not have to Organisms do not have to grow in the food before it is grow in the food before it is

eaten: eaten:

Food Borne InfectionsFood Borne Infections• Organisms do not have to grow in the Organisms do not have to grow in the

food before it is eaten: food before it is eaten: Bacteria Bacteria Typhoid Typhoid Cholera Cholera TB TB Brucellosis Brucellosis Q-fever Q-fever

Anthrax Anthrax

Viruses Viruses Hepatitis A Hepatitis A Polio Polio Anual incidence Anual incidence Rotavirus Rotavirus Enteroviruses Enteroviruses

Parasites Parasites Amoeboid disentry Amoeboid disentry Toxoplasmosis Toxoplasmosis Giardia lamblia Giardia lamblia Cryptosporidium Cryptosporidium Nematode Nematode Helminths Helminths

Typhoid feverTyphoid fever

– Diagnosis of typhoid feverDiagnosis of typhoid feverBlood cultures are positive during the first Blood cultures are positive during the first

week and after the second weekweek and after the second weekStool cultures and sometimes urine Stool cultures and sometimes urine

cultures are positive after the second weekcultures are positive after the second weekThe Widal test is a serological test for The Widal test is a serological test for

antibodies against antibodies against Salmonella typhi. Salmonella typhi. 10% of those infected become short term 10% of those infected become short term

carriers and a smaller % become long-term carriers and a smaller % become long-term carriers due to persistence of the bacteria carriers due to persistence of the bacteria in the gallbladder or urinary bladder.in the gallbladder or urinary bladder.

TyphoidTyphoid

fever fever

SalmonellosSalmonellosisis

Salmonellosis cases in NZ from 1980 to 2004

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Other BacteriaOther Bacteria

TB TB

BrucellosisBrucellosis

Q-feverQ-fever

AnthraxAnthrax

Incidence of TBIncidence of TB• Tuberculosis (TB) remains the leading cause of Tuberculosis (TB) remains the leading cause of

death worldwide from a single infectious disease death worldwide from a single infectious disease agent. Indeed up to agent. Indeed up to 1/2 of the world's 1/2 of the world's populationpopulation is infected with TB. is infected with TB.

• The registered number of new cases of TB The registered number of new cases of TB worldwide roughly correlates with economic worldwide roughly correlates with economic conditions: conditions:

• the highest incidences are seen in those the highest incidences are seen in those countries with the lowest gross national products. countries with the lowest gross national products.

• WHO estimates that eight million people get TB WHO estimates that eight million people get TB every year, of whom 95% live in developing every year, of whom 95% live in developing countries. countries.

• An estimated 2 million people die from TB every An estimated 2 million people die from TB every year. year.

MortalityMortality

• It is estimated that between 2000 and 2020, It is estimated that between 2000 and 2020, nearly nearly one billionone billion people will be newly infected, people will be newly infected, 200 million people will get sick, and 200 million people will get sick, and 35 million 35 million will diewill die from TB from TB

• After a century of decline TB is increasing and After a century of decline TB is increasing and there are strains emerging which are resistant to there are strains emerging which are resistant to antibiotics. antibiotics.

• This excess of cases is attributable to the This excess of cases is attributable to the changes in the social structure in cities, the changes in the social structure in cities, the human immunodeficiency virus epidemic, and human immunodeficiency virus epidemic, and failure of most cities to improve public health failure of most cities to improve public health programs, and the economic cost of treating. programs, and the economic cost of treating.

HISTORYHISTORY

• TB is an ancient infectious disease caused TB is an ancient infectious disease caused by by Mycobacterium tuberculosisMycobacterium tuberculosis. .

• It has been known since 1000 B.C., It has been known since 1000 B.C., • Since TB is a disease of respiratory Since TB is a disease of respiratory

transmission, optimal conditions for transmission, optimal conditions for transmission include: transmission include: – overcrowdingovercrowding – poor personal hygienepoor personal hygiene – poor public hygienepoor public hygiene

1/2 of the world's population is 1/2 of the world's population is infectedinfected

• With the increased incidence of AIDS, TB With the increased incidence of AIDS, TB has become more a problem in the U.S., has become more a problem in the U.S., and the world.and the world.

• It is currently estimated that 1/2 of the It is currently estimated that 1/2 of the world's population (3.1 billion) is infected world's population (3.1 billion) is infected with with Mycobacterium tuberculosis. Mycobacterium tuberculosis.

• Mycobacterium aviumMycobacterium avium complex is complex is associated with AIDS related TB. associated with AIDS related TB.

Center for Food Security and Center for Food Security and Public Health Iowa State Public Health Iowa State

University - 2004University - 2004

BrucellaBrucella spp. spp.

• Gram negative, coccobacilli bacteriaGram negative, coccobacilli bacteria

• Facultative, intracellular organismFacultative, intracellular organism

• Environmental persistenceEnvironmental persistence– Temp, pH, humidityTemp, pH, humidity– Frozen and aborted materialsFrozen and aborted materials

• Multiple speciesMultiple species



Species Biovar/Serovar

Natural Host Human Pathogen

B. abortus 1-6, 9 cattle yes

B.melitensis 1-3 goats, sheep yes

B. suis 1, 3 swine yes

2 hares yes

4 reindeer, caribou

yes

5 rodents yes

B. canis none dogs, other canids

yes

B. ovis none sheep no

B. neotomae none Desert wood rat

no

B. maris marine mammals

?



The Many Names of BrucellosisThe Many Names of Brucellosis

Human DiseaseHuman Disease

• Malta FeverMalta Fever

• Undulant FeverUndulant Fever

• Mediterranean FeverMediterranean Fever

• Rock Fever of Rock Fever of GibraltarGibraltar

• Gastric FeverGastric Fever

Animal DiseaseAnimal Disease

• Bang’s DiseaseBang’s Disease

• Enzootic AbortionEnzootic Abortion

• Epizootic AbortionEpizootic Abortion

• Slinking of CalvesSlinking of Calves

• Ram EpididymitisRam Epididymitis

• Contagious AbortionContagious Abortion



Sir David Bruce (1855-1931)

•British Army physician and microbiologist who discovered Micrococcus melitensis

Professor FEG Cox. The Wellcome Trust, Illustrated History of Tropical Diseases



Transmission to HumansTransmission to Humans

• Conjunctiva or broken skin Conjunctiva or broken skin contacting infected tissuescontacting infected tissues– Blood, urine, vaginal discharges, Blood, urine, vaginal discharges,

aborted fetuses, placentasaborted fetuses, placentas

• Ingestion Ingestion – Raw milk & unpasteurized dairy Raw milk & unpasteurized dairy

productsproducts– Rarely through undercooked meatRarely through undercooked meat



Transmission to HumansTransmission to Humans

• Inhalation of infectious aerosolsInhalation of infectious aerosols– Pens, stables, slaughter housesPens, stables, slaughter houses

• Inoculation with vaccinesInoculation with vaccines– B. abortusB. abortus strain 19, RB-51 strain 19, RB-51 – B. melitensisB. melitensis Rev-1 Rev-1 – Conjunctival splashes, injectionConjunctival splashes, injection

• Person-to-person transmission is very rarePerson-to-person transmission is very rare

• Incubation varies Incubation varies – 7-21 days to several months7-21 days to several months



B. melitensisB. melitensis • Latin America, Middle East, Latin America, Middle East,

Mediterranean, eastern Europe, Mediterranean, eastern Europe, Asia, and parts of Africa Asia, and parts of Africa

• Accounts for most human casesAccounts for most human cases– In the Mediterranean and Middle In the Mediterranean and Middle

EastEast•Up to 78 cases/100,000 Up to 78 cases/100,000

people/yearpeople/year•Arabic Peninsula 20% Arabic Peninsula 20%

seroprevalenceseroprevalence

• Recent emergence in cattle on Recent emergence in cattle on Middle Eastern intensive dairy Middle Eastern intensive dairy farmsfarms



B. abortusB. abortus• WorldwideWorldwide

• Some countries have Some countries have eradicatederadicated

• Notifiable disease in many Notifiable disease in many countriescountries– Poor surveillance and Poor surveillance and

reporting due to lack of reporting due to lack of recognitionrecognition

– Fever of Unknown Origin Fever of Unknown Origin (FUO)(FUO)



B. suisB. suis

• Biovars 1 and 3Biovars 1 and 3– Worldwide problems where swine are Worldwide problems where swine are

raisedraised

• FreeFree– United Kingdom, Canada United Kingdom, Canada

• EradicatedEradicated– Holland, Denmark Holland, Denmark

• Low IncidenceLow Incidence– Middle East, North AfricaMiddle East, North Africa



B. canisB. canis

• Poorly understood Poorly understood

• 1-19% prevalence in 1-19% prevalence in United StatesUnited States

• Rarely causes disease Rarely causes disease in humansin humans



Brucellosis in U.S.: 1972-2002Brucellosis in U.S.: 1972-2002

1972 1977 1982 1987 1992 1997 2002 Year

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BrucellosisBrucellosis

• United StatesUnited States– Approximately 100 cases per yearApproximately 100 cases per year– Less than 0.5 cases/100,000 peopleLess than 0.5 cases/100,000 people– Mostly California, Florida, Texas, VirginiaMostly California, Florida, Texas, Virginia– Many cases associated Many cases associated

with consumption of with consumption of foreign cheesesforeign cheeses



PrognosisPrognosis

• May last days, months or yearsMay last days, months or years

• Recovery is commonRecovery is common

• Disability is often pronounced Disability is often pronounced

• About 5% of treated cases relapseAbout 5% of treated cases relapse•Failure to complete the treatment regimenFailure to complete the treatment regimen

•Sequestered infection requiring surgical Sequestered infection requiring surgical drainagedrainage

• Case-fatality rate: <2% ( untreated)Case-fatality rate: <2% ( untreated)– Endocarditis caused by Endocarditis caused by B. melitensisB. melitensis



Human DiseaseHuman Disease• NeurologicalNeurological

– Depression, mental fatigue Depression, mental fatigue

• CardiovascularCardiovascular– Endocarditis resulting in deathEndocarditis resulting in death

• Chronic brucellosis is hard to defineChronic brucellosis is hard to define– Length, type and response to treatment Length, type and response to treatment

variablevariable– Localized infectionLocalized infection

• Blood donations of infected should Blood donations of infected should not be acceptednot be accepted

•Q FeverQ Fever



The OrganismThe Organism

• Coxiella burnetiiCoxiella burnetii– Rickettsial agentRickettsial agent– Obligate intracellular parasiteObligate intracellular parasite– Stable and resistantStable and resistant– Killed by pasteurizationKilled by pasteurization– Two antigenic phasesTwo antigenic phases

•Phase 1: virulentPhase 1: virulent

•Phase 2: less pathogenicPhase 2: less pathogenic



HistoryHistory

• 1935 1935 – 1st described in Queensland, Australia1st described in Queensland, Australia– Found in ticks in MontanaFound in ticks in Montana

• OutbreaksOutbreaks– Among military troopsAmong military troops

•When present in areas with When present in areas with infected animalsinfected animals

– Cities and townsCities and towns•Downwind from farmsDownwind from farms•By roads traveled by animalsBy roads traveled by animals



TransmissionTransmission

• AerosolAerosol– Parturient fluidsParturient fluids

• 101099 bacteria per bacteria per gram of placentagram of placenta

– Urine, feces, milkUrine, feces, milk– Wind-borneWind-borne

• Direct contactDirect contact

• FomitesFomites

• IngestionIngestion

• Arthropods (ticks)Arthropods (ticks)

http://www.asahi-net.or.jp/~xs3d-bull/secret_page/fumis_page/cat_and_kittens.jpg



TransmissionTransmission

• Person-to-person (rare)Person-to-person (rare)– Transplacental (congenital)Transplacental (congenital)– Blood transfusionsBlood transfusions– Bone marrow transplantsBone marrow transplants– Intradermal inoculationIntradermal inoculation– Possibly sexually transmittedPossibly sexually transmitted



EpidemiologyEpidemiology

• WorldwideWorldwide– Except New ZealandExcept New Zealand

• ReservoirsReservoirs– Domestic animalsDomestic animals

•Sheep, cattle, goatsSheep, cattle, goats

•Dogs, catsDogs, cats

– BirdsBirds– ReptilesReptiles– WildlifeWildlife



EpidemiologyEpidemiology

• Occupational and Occupational and environmental hazards environmental hazards– Farmers, producersFarmers, producers– Veterinarians and techniciansVeterinarians and technicians– Meat processors, abattoirMeat processors, abattoir– Laboratory workersLaboratory workers



Human DiseaseHuman Disease

• Incubation: 2-5 weeksIncubation: 2-5 weeks

• One organism may cause diseaseOne organism may cause disease

• Humans are dead-end hostsHumans are dead-end hosts– Usually show clinical signs of illnessUsually show clinical signs of illness

• DiseaseDisease– Asymptomatic (50%)Asymptomatic (50%)– AcuteAcute– ChronicChronic



Acute InfectionAcute Infection

• Flu-like, self limiting Flu-like, self limiting

• Atypical pneumonia (30-50%)Atypical pneumonia (30-50%)– Non-productive cough, chest painNon-productive cough, chest pain– Acute respiratory distress possible Acute respiratory distress possible

• HepatitisHepatitis

• Skin rash (10%)Skin rash (10%)

• Other signs (< 1%)Other signs (< 1%)– Myocarditis, pericarditis, meningoencephalitisMyocarditis, pericarditis, meningoencephalitis

• Death: 1-2%Death: 1-2%



Chronic DiseaseChronic Disease

• 1-5% of those infected1-5% of those infected– Prior heart disease, pregnant women, Prior heart disease, pregnant women,

immunocompromisedimmunocompromised

• EndocarditisEndocarditis

• OtherOther– OsteomyelitisOsteomyelitis– Granulomatous hepatitisGranulomatous hepatitis– CirrhosisCirrhosis

• 50% relapse rate after antibiotic therapy50% relapse rate after antibiotic therapy



Risk to Pregnant WomenRisk to Pregnant Women

• Most asymptomaticMost asymptomatic

• Transplacental transmissionTransplacental transmission

• Reported complicationsReported complications– In-utero deathIn-utero death– Premature birthPremature birth– Low birth weightLow birth weight– PlacentitisPlacentitis– ThrombocytopeniaThrombocytopenia



PrognosisPrognosis

• Overall case-fatality rate <1 - 2.4%Overall case-fatality rate <1 - 2.4%

• 50% cases self-limiting50% cases self-limiting

• Only 2% develop severe diseaseOnly 2% develop severe disease

• Active chronic diseaseActive chronic disease– Usually fatal if left untreatedUsually fatal if left untreated– Fatality for endocarditis: 35-55%Fatality for endocarditis: 35-55%– 50-60% need valve replacement50-60% need valve replacement



CaseCase

• Male dairy farmerMale dairy farmer– Age 46Age 46– Sudden onsetSudden onset

•Fever, chills, coughFever, chills, cough

•Weight lossWeight loss

– Initially thought it was influenzaInitially thought it was influenza– Symptoms persisted for 2 weeks Symptoms persisted for 2 weeks – Presented to emergency room Presented to emergency room

•Again influenza was the diagnosisAgain influenza was the diagnosis



Large Animal CaseLarge Animal Case

• Referral to infectious disease specialistReferral to infectious disease specialist– Tested positive for Q feverTested positive for Q fever– Antibiotics for 5 daysAntibiotics for 5 days– Resolved in 2 weeksResolved in 2 weeks

• EpidemiologyEpidemiology– No recent calvings on his farmNo recent calvings on his farm– Two beef cattle herds across the road Two beef cattle herds across the road

•2 out of 14 tested positive for Q fever2 out of 14 tested positive for Q fever



Small Animal CaseSmall Animal Case• 1985, Nova Scotia, Canada1985, Nova Scotia, Canada

– 33 cases of Q fever33 cases of Q fever•25 were exposed to cat25 were exposed to cat•17 developed cough17 developed cough•14 developed pneumonia14 developed pneumonia

– Most common symptomsMost common symptoms•Fever, sweats, chills, fatigue, myalgia, Fever, sweats, chills, fatigue, myalgia,

headacheheadache

– Cat tested positive for Cat tested positive for C. burnetiiC. burnetii•1:152 to phase I antigen1:152 to phase I antigen•1:1024 to phase II antigen1:1024 to phase II antigen




• Sheep, cattle, goatsSheep, cattle, goats– Usually asymptomaticUsually asymptomatic– Reproductive failureReproductive failure

•Abortions, stillbirthsAbortions, stillbirths•Retained placentaRetained placenta• InfertilityInfertility•Weak newbornsWeak newborns•Low birth weightsLow birth weights•Mastitis in dairy cattleMastitis in dairy cattle

– Carrier stateCarrier state




• Other animal speciesOther animal species– Dogs, cats, horses, pigs, camels, buffalo, Dogs, cats, horses, pigs, camels, buffalo,

pigeons, other fowlpigeons, other fowl– AsymptomaticAsymptomatic– Reproductive failureReproductive failure

• Laboratory AnimalsLaboratory Animals– Rats, rabbits, guinea pigs, hamstersRats, rabbits, guinea pigs, hamsters– Varies from asymptomatic to fever, Varies from asymptomatic to fever,

granulomas, or deathgranulomas, or death



Morbidity and MortalityMorbidity and Mortality

• Prevalence unknownPrevalence unknown– Endemic areasEndemic areas

•18-55% of sheep with antibodies18-55% of sheep with antibodies

•82% of dairy cattle82% of dairy cattle

• Morbidity in sheep: 5-50%Morbidity in sheep: 5-50%



Prevention and ControlPrevention and Control

• PasteurizationPasteurization

• VaccinationVaccination– Human and animalHuman and animal– Not available in U.S.Not available in U.S.

• Eradication not practicalEradication not practical– Too many reservoirsToo many reservoirs– Constant exposureConstant exposure– Stability of agent in environmentStability of agent in environment



Prevention and ControlPrevention and Control

• EducationEducation– Sources of infectionSources of infection

• Good husbandryGood husbandry– Disposal of birth products (incinerate)Disposal of birth products (incinerate)

•Lamb indoors in separate facilities Lamb indoors in separate facilities

– DisinfectionDisinfection•0.05% chlorine0.05% chlorine

•1:100 Lysol1:100 Lysol

• Isolate new animalsIsolate new animals

Anthrax

•How heat resistant is Bacillus anthracis (B. Anthracis)?

Spores•Moist heat resistance •D value at 90ºC (194ºF) - 2.5-7.5

minutes •D value at 95ºC (203ºF) - 1.7-4.2

minutes• Not That much killed with

thorough cooking

Epidemiology of Anthrax in Animal and

Human Hosts

Clinical Presentation of Anthrax Gastrointestinal (Ingestion) Anthrax

Virtually 100% fatal Abdominal pain Hemorrhagic ascites Paracentesis fluid may reveal gram-positive rods

Treatment & Prophylaxis Treatment

• Penicillin is drug of choice• Erythromycin, chloramphenicol acceptable alternatives• Doxycycline now commonly recognized as

prophylactic

Vaccine (controversial) Laboratory workers Employees of mills handling goat hair Active duty military members Potentially entire populace of U.S. for herd immunity

food borne infections organisms do not have to grow in the food before it is eaten: organisms do not...

Documents

century of decline tb

economic conditions

excess of cases

developing countries

infections organisms

week stool cultures

economic cost of tr

urine cultures