So far, spread of H5N1 HPAI from birds to people has only occurred as a result of...
extensive direct contact with infected birds [home slaughter/defeathering]
has there been human-to-human transmission of avian influenza A?
explain the Pathogenesis of Human Disease of HPAI flu A, H5N1. what is mortality like?
“Cytokine Storm”= An Innate exaggerated immune response caused by rapidly proliferating and highly activated T-cells or natural killer (NK) cells, which leads to a Severe Flu-like + lower respiratory tract symptoms > Pneumonia ..Multi-organ failure. Mortality: high among hospitalized patients
is there a vx for HPAI?
yes-- for birds AND ONE FOR HUMANS NOW ALSO AVAILABLE
why is the vx for HPAI controversial? (PROS and CONS)
PROS: Reducing the clinical signs, diminishing the duration/extent of shedding. CONS: Some healthy Vaccinated birds become infected, shed > become a source of infection for others! In all countries which have applied vaccination to control H5N1, infection has become endemic, might not protect against variants
*All H__ and H__ viruses are notifiable when in poultry!
5 and 7
if there is avian flu of H5 or H7 in the US, what must the USDA do?
report to OIE
does poultry have to be vx against AI?
No Federal program mandating vaccination of birds but AI testing/surveillance of birds by States/federal
what are 4 ways the USDA does surveillance of AI?
(1) survey live bird markets (2) Commercial –preslaughter surveillance of broilers - test each flock on the farm before it is sent to slaughter (3) Backyard flocks: encourage biosecurity practices (4) watch migratory bird populations (Additionally, birds that show signs of illness are tested)
USDA Import restrictions about AI?
Quarantine & tests imported live birds for foreign animal diseases eg. HPAI H5N1.>Trade restrictions on imports from countries>endemic HPAI H5N1. Also, Agricultural inspections of … for illegally smuggled poultry/ products conducted by Department of Homeland Security (DHS) - Customs and Border Protection
what other species can H5N1 affect, and how?
cat, Domestic cats infected if fed uncooked meat from H5N1- infected chickens > spread infection >other cats
Equine-Canine Influenza is H__N_
H3N8 (three likes dogs but Octavian rides a horse)
is there a vx for H3N8?
(equine canine flu) Yes, for horses
what is H1N1?
the predominant circulating influenza virus worldwide. It is a mix of N.American swine influenza viruses, North American avian influenza viruses, Human influenza viruses, [N] and matrix [M] genes from Eurasian [found in both Asia &Europe] Swine influenza viruses
can H1N1 go from human to human?
what kinda humans are most at risk for H1N1? how is it transmitted?
Aerosol human-human. People <25yrs most at risk
is there a vx for H1N1?
yes- but both H1N1 vx and seasonal flu vx < risk of flu by 70% to 90% in healthy adults.. ALSO one for pigs
how did "swine flu" (H1N1) start?
in people! although swine CAN get infected, there is actually a vx to protect them from people!
is there a H1N1 vx for pets?
Swine Type A Influenza Viruses--> Swine origin Influenza virus [S-OIV’s]--> what should be noted about this?
NOT H1N1 of people!
when is it appropriate to say "swine flu" ?
The term “swine flu” should only be used to refer to disease due to influenza viruses circulating in swine
Influenza viruses that circulate in pigs(Different from influenza viruses in people)--> what are the 4 main subtypes?
H1N1, H1N2, H3N2, H3N1
H3N2 affects who and is aka?
PIGs, aka [TRIG cassette] bc Contain a combination of genes from avian, swine and human viruses known as the triple reassortant internal gene(t.r.i.g.)
do Swine origin Influenza virus [S-OIV’s] infect humans?
Do not normally infect humans! When human infections with these viruses occur, these viruses are called “variant” viruses (denoted “v”)
although rare, if a S-OIV (swine origin influenza virus) infects a human, what's the transmission?
MOST human cases>close contact with infected pigs. ~**S-OIV’s not transmitted to humans by food!!!
hwo are Swine origin Influenza virus [S-OIV’s] transmitted between pigs?
Aerosol-Close contact between pigs, OR Contaminated objects >infected -uninfected pigs.
what are the clinical signs of swine flu in swine?
RNA Arbovirus: acronym for ARthropod-BOrne viruses (flaviviridae-- because nile water is flavorful)
what are the 2 proteins which give WNV its biological properities
E and M
what does the E protein of WNV do?
Mediates virus-host cell binding (E for ENTER)
which surface protein of WNV elicits most virus-neutralizing antibodies, which means it is useful for vxs?
E (e for enter and e for EEEEK! Abs, attack!!)
is WNV reportable?
no because it's endemic
whats the WNV vector?
mosquitos, esp. the sp. Culex (not all sp competent vectors)
whats the WNV maintainance host?
wild birds, esp. Birds of the Corvidae (ravens, jays, crows). Occasionally poultry, mainly geese & ostriches
are birds affected by WNV?
some can die from systemic infection with myocarditis and encephalitis, most survive, develop life-long immunity, and then can become carriers
what are accidental/dead end hosts of WNV?
horses and humans
how do humans get WNV?
bite from mosquito 99% of exposures (technically, can also get from transfusions, transplants, Mother-to-Child. During pregnancy & breastfeeding rarely, Laboratory-acquired human infections)
can humans get WNV from horses?
can humans get WNV from humans?
how is WNV dz like in humans?
typically develop symptoms 3 - 14 days after they are bitten by the infected mosquito. Majority are asymptomatic. Some develop mild symptoms.. headache, fever. Some> severe disease, CNS including encephalitis
which age is a risk factor for getting a severe WNV infection?
hows WNV dz like in horses?
Differences in susceptibility of individual horses to neurologic disease following infection. Strains of WNV vary in their virulence to horses...Many asymptomatic, others…CNS signs. Some die spontaneously or are slaughtered to avoid excessive suffering.
in a horse, differentials for WNV?
Rabies, EEE, WEE, etc..
what is dz like in birds with WNV?
Not pathogenic in many species of birds. High mortality in some spp. of wild birds in the US, >American crow & other corvids (ravens, jays) <--These birds are the ones that develop high viremia & transmit the virus on to uninfected mosquitoes.
how do you detect WNV (dX) in horses/humans?
ELISA Serological detection of IgM antibody (IgM is M is upside down W)
is there a WNV vx for horses?
yes (DOSENT prevent infxn tho)
downside to the WNV vx in horses?
vaccinated horses and foals from vaccinated mares may also test positive bc of IgM formed from the vx
if you cannot differentiate the vx from exposure of WNV, what must vets do?
Vet must consider not only the serology results, but the clinical symptoms and the possibility of other CNS diseases including rabies, EEE, WEE and EPM (Equine protozoal myeloencephalitis)
is there a human vx for WNV?
no (Therefore, prevention of arboviral disease depends on efforts to reduce vector densities)
what kinda precautions should VETS be taking with WNV?
Vets and others performing necropsies or handling specimens from infected animals that may shed the virus in oral, respiratory secretions, urine or faeces. WEAR protective clothing, glove, respiratory protection
when do you wanna vx horses for WNV?
Immunization should be timed to maximize protection during the summer and fall when virus exposure is greatest (ie, mosquito season)
Eastern/Western/Venezuelan Equine Encephalomyelitis--> caused by what kinda virus?
zoonotic RNA viruses, Alphavirus (Family Togaviridae) ( all these acronyms are an alpha pain in my butt)
EEE/WEE/VEE are what category?
essential reservoir host for EEE?
essential reservoir host for WEE?
essential reservoir host for VEE?
RODENTS, NOT BIRDS!! (venezuela must be full of rats or something)
biological vector for EEE?
biological vector for WEE?
biological vector for VEE?
*how do the accidental/dead end hosts differ between EEE/WEE/VEE?
in EEE/WEE, HORSES AND PEOPLE are dead end hosts. However, in VEE, only people are dead end hosts, and horses are AMPLIFIER hosts
whch arbovirus has horses as an amplifier host?
which arbovirus doesnt have birds as a maintainance host? what IS the maintainance host?
which arbovirus is reportable?
Disease in Horses with infections of EEE/WEE?
>fever, lethargy, ….., paresis, seizures and coma in fatal cases
EEE dz in humans
Encephalitis.No specific treatment symptomati. Illness may >disorientation, seizures, coma. Significant CNS damage in most survivors
most severe mosquito-transmitted diseases in the US?