Lecture 39 11/26/24 Flashcards by Danika Boltz

What are the characteristics of influenza?

-classified into subtypes based on surface antigens
-hemagglutinin has 18 types
-neuraminidase has 11 types

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How does HPAI differ from LPAI?

HPAI:
-causes severe disease in poultry
-only subtypes H5 or H7
-interspecies transmission from birds to mammals
-reportable and foreign animal disease
LPAI:
-causes mild disease in poultry
-contains other H subtypes, including non-HPAI H5 and H7
-LPAI H5 and H7 can mutate into HPAI

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What are the characteristics of waterfowl as reservoirs?

-natural reservoirs for influenza A
-carry all known H and N antigens, usually in LPAI form
-predominant subtypes change periodically

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What are the characteristics of antigenic drift?

-continual process
-point mutations in virus cause small changes
-reason flu vaccines are updated yearly

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What are the characteristics of antigenic shift?

-sporadic event
-reassortment of 8 genome segments
-may result in new H or N surface proteins

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What are the characteristics of influenza virus emergence in humans?

-avian and swine flu viruses do not normally infect humans
-frequent mutations occur through antigenic drift and shift events
-swine are proposed mixing vessels of influenza viruses

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What are the characteristics of avian influenza in people?

-50-60% mortality
-clinical signs include fever, lower resp. disease, and diarrhea

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What are the clinical signs of LPAI in birds?

-resp. disease
-decreased egg production
-secondary infections
-variable morbidity and mortality

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What are the clinical signs of HPAI in birds?

-sudden death
-variable resp., GI, and neuro signs
-up to 100% mortality

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How is avian influenza diagnosed?

-pathology
-PCR
-serology
-virus isolation
-in vivo determination of pathogenicity

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How is avian influenza prevented in people?

-vaccine licensed by FDA but only for use in the event of an H5N1 outbreak
-do not handle birds that could be infected
-wear appropriate PPE
-vaccination in birds

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What are the characteristics of canine influenza H3N8?

-horses long considered dead-end hosts
-equine influenza H3N8 first emerged in greyhounds in Florida
-HA of canine influenza virus contains 5 conserved amino acids that distinguishes it from equine influenza
-single trans-species transmission event with subsequent lateral spread between dogs

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What are the characteristics of canine influenza H3N2?

-brought in by groups rescuing dogs from South Korea
-has also caused outbreaks in shelter cats

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Who must be informed when reportable/foreign animal diseases are discovered?

-state veterinarian
-district veterinarian in charge (federal)

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What are the characteristics of hantavirus?

-negative sense ssRNA bunyavirus
-Sin Nombre strain is most common in US
-Sin Nombre causes hantavirus pulmonary syndrome
-other strains can cause hemorrhagic fever with renal syndrome

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What is the epidemiology of hantavirus in the US?

-case fatality rate of 36%
-most common in males
-average age of 38 years old
-typically occurs in caucasian individuals
-nearly all cases occur west of Mississippi River
-incubation of 1 to 5 weeks after exposure

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What are the characteristics of hantavirus transmission?

-rodents are reservoirs
-humans and other mammals typically infected by inhaling virus particles from rodent urine, feces, and nests
-virus can also enter through broken skin, conjunctiva, other mucus membranes, rodent bites, or ingestion

What are the clinical signs during the initial phase of hantavirus pulmonary syndrome?

-fever
-myalgia
-headache

What are the clinical signs during the cardiopulmonary phase of hantavirus pulmonary syndrome?

-abrupt resp. distress
-cough
-tachypnea
-pulmonary edema
-cardiac abnormalities

What are the characteristics of hantavirus pulmonary syndrome disease progression?

-may be rapid after onset of cardiopulmonary phase
-may require hospitalization and mechanical ventilation

Which other symptoms can occur with hantavirus pulmonary syndrome?

-mild kidney disease
-hemorrhagic disease (rare)

How long is the incubation period for hemorrhagic fever with renal syndrome?

1 to 6 weeks

What are the disease stages in severe cases of hemorrhagic fever with renal syndrome?

-febrile
-hypotensive/proteinuric
-oliguric
-diuretic
-convalescent

What are the renal signs that occur with hemorrhagic fever with renal syndrome?

-proteinuria -> oliguria -> polyuria
-hypotension
-nausea and vomiting
-kidney failure
-lung or neurological signs

What are the characteristics of seoul virus?

-type of hantavirus -typically causes no or mild symptoms -can cause serious illness that requires hospitalization

How is seoul virus transmitted to people?

-contact with urine, droppings, or saliva of infected rats -breathing in virus particles -bitten by infected rat

How is seoul virus prevented?

-testing new rats before introduction into new home, especially multi-rat homes and breeding facilities -keep wild rats away from pet rats -do not recommend pet rodents for families with children younger than 5 years old, pregnant women, or immunocompromised individuals

What are the prevention steps for hantavirus?

-avoid rodents and their droppings -wear a mask to prevent inhalation when working in potentially contaminated areas -disinfect surfaces

What are the characteristics of Chlamydia psittaci?

-obligate gram neg. intracellular bacteria -elementary and reticulate bodies

What are the different serovars of Chlamydia psittaci?

-A: endemic is psittacines, causes human cases -B: endemic in pigeons and turkeys; causes abortion in cattle -C/D: occupational hazards for slaughterhouse workers

What is the epidemiology of Chlamydia psittaci?

-worldwide -true incidence unknown -cases thought to be greatly underreported -reportable disease in most states

How does Chlamydia psittaci transmit to humans?

-inhalation -mouth to beak -direct contact -person to person/venereal

What are the characteristics of psittacosis in humans?

-incubation period of 1-4 weeks -abrupt onset of clinical signs -signs include fever, chills, headache, malaise, myalgia, sore throat, cough, dyspnea, splenomegaly, and rash -can progress to pneumonia, endocarditis, myocarditis, or encephalitis -treated with doxycycline or azithromycin

How is psittacosis diagnosed in humans?

-culture -4 fold rise in paired titers -PCR

What are the clinical signs of psittacosis in birds?

-incubation period of 3 days to 3 weeks -often asymptomatic -anorexia -weight loss -diarrhea -yellowish droppings -sinusitis -resp. distress -nervous signs

How are birds treated for psittacosis?

doxy for 45 days

What are the characteristics of psittacosis shedding?

-carriers may appear healthy and shed intermittently -shedding activated by stress -shedding is greatest in young birds

How is psittacosis diagnosed in birds?

-pathologic diagnosis -culture -antibody tests -antigen tests

How is psittacosis prevented in humans?

-notifiable disease in most states -purchase birds from reputable shops/sources -wash hands regularly after handling -do not touch birds' beak or face to mouth -do not keep psittacines if immunosuppressed -disinfect cages

How is psittacosis prevented in birds?

-ended large scale importation -quarantine of imports -closed flocks -records of all transactions -quarantine all new birds joining flocks for 30 days -acquire birds from reputable sources -do not overcrowd -disinfect surfaces

What is important for veterinarians to know about psittacosis?

-check state rules for reporting requirements -inform clients, employees, and co-workers about zoonotic risks and how to mitigate them -be aware of clinical signs in humans -consider psittacosis in any lethargic bird