avian influenza threat, human infections and pandemic potential

Avian Influenza threat, human infections and

pandemic potential

Date : 23 \3\2012Presentation By :- Dr. Eman Diab

introduction

Introduction AVI is a highly contagious viral disease with up

to 100 percent mortality in domestic fowl. Caused by influenza A virus subtypes H5, H9

and H7. All types of birds are susceptible to the virus,

but outbreaks occur most often in chickens and turkeys.

The infection may be brought by migratory wild birds which can carry the virus, but show no signs of disease.

Electron micrograph for the influenza virus A, Ref.

History of infection

History of human infection First avian influenza virus to infect humans

occurred in Hong Kong in 1997. The epidemic was linked to chickens and classified as avian influenza A (H5N1).

More than 560 cases have been identified since then, with deaths worldwide exceeding 300.

Human cases of highly pathogenic bird flu have been largely confined to Southeast Asia and Africa.

Ref.

History of poultry infection by AI 1878 in Italy &known as “fowl plague” Its typed as influenza virus at 1955 . classified to types (A , B, C ) In the late 1990s, a new strain of bird flu arose that

was remarkable for its ability to cause severe disease and death, especially in domesticated birds such as ducks, chickens, or turkeys. As a result, this strain was called highly pathogenic (meaning very severe) avian influenza. It began in Asia & China then spread world wide possibly through migratory birds

It began in Asia & China then spread world wide possibly through migratory birds..

Since the identification of highly pathogenic influenza, infected birds have been found in Asia, Europe, the Middle East, and Africa.

Careful control measures, including destroying infected flocks and vaccinating healthy birds, have reduced the number of cases, but the virus continues to exist in poultry flocks in areas of Asia and Africa. Bird flu from the highly pathogenic strain is not found in the United States at this time

History of poultry infection by AI

Cause of AI-RNA virus.-8 segments . -Enveloped virus. -Single strand . -Orthomyxoviridae family.

-Its polymorphic shape may be circular , concave……

Ref. Dr. Madiha (prof. dr. of virology in Damanhur university)

Ref. (net. http//

Budding of the virus after completing

Genetic classification

Ref.net. http//

Genetic classification-according to NP -:

( A, B, C) -Type A :- in birds

-Type B , C :- specific to human being (due to having specific receptors) don’t transmit for birds from

. humans

According to surface protein -There are several subtypes, labeled

according to an H number (for the type of hemagglutinin )

and N number (for the type of neuraminidase) .

-There are 16 different H antigens( H1 to H16 )

and nine different N antigens (N1 to N9).So there 144 possible combinations.

Ref. Dr. Madiha (prof dr. of virology)

•Some variants are identified and named according to:• the isolate they resemble, thus are presumed to share lineage

(example Fujian flu virus-like); • their typical host (example human flu virus); • their subtype (example H3N2); • their deadliness (example LP, low pathogenic).

•So a flu from a virus similar to the isolate A/Fujian/411/2002(H3N2) is called Fujian flu, human flu, and H3N2 flu.

•Variants are sometimes named according to the species (host) in which the strain is endemic or to which it is adapted. •The main variants named using this convention are:

• Bird flu• Human flu• Swine influenza• Equine influenza• Canine influenza

Nomenclature of AI

Ex.

(A/chicken/Italy/330/97/H5N2)

A refers to type A of AI.Chicken is the infected species.Italy is place where it had been isolated.330 gene bank (inter only in zoonontic diseases).79 discovered at 1997.H5N2 sub type of the virus.

Nomenclature of AI

susceptibility

Most susceptible animals

-Chickens.( ducks &gees- )Water fowls

-Birds-Swine

-equines

The most susceptible people to AI infection

.-Farmers and others who work with poultry0Travelers visiting affected countries

0-Those who touch an infected bird-Those who eat raw or undercooked poultry

0meat, eggs, or blood from infected birds-Health care workers and household contacts

of patients with avian influenza may also be at an increased risk of the bird flu.

Mode of transmission

Mode of transmission-Through inhalation of contaminated

droplets.

-Through ingestion of contaminated food & water or uncooked food.

-Through direct contact between infected birds or between infected birds and humans.

Clinical signs of AI

Clinical signs in humanSymptoms of avian flu infection in humans depend on the strain of virus.Infection with the H5N1 virus in humans causes typical flu-like symptoms, which might include:

)Cough( dry or productiveDiarrhea

Difficulty breathingFever greater than 100.4°F (38°C)

HeadacheMalaiseMuscle achesRunny nose

Sore throat

Clinical signs in birds-In poultry tropism of AI is upper respiratory tract.

-Signs variable , Depends on-: age , severity of virus , other infection

complications ,immune status , dose of infection.Ex .

Depression &decrease in feed in take Drop in egg productionDiscoloration in comb &wattlesSubcutaneous edema in face Hemorrhage in thigh muscles &on shank bone .

-Nasal discharge & ocular discharge-Greenish yellowish diarrhea-Rales & coughing

Ref. net. Sites Http//

Cyanosis in combe

Edema in face

Piticeal hemorrhages on proventriculus

PM. lesions

Ref. net sites Http//

Diagnosis

Exams &tests for humans:--If you think you have been exposed to avian influenza, call your health care

provider before your visit. This will give the staff a chance to take proper precautions that will protect them and other patients during your office visit.

-Tests to identify the avian flu exist but are not widely available.-test for diagnosing strains of bird flu in people suspected of having the virus

gives preliminary results within 4 hours. Older tests took 2 to 3 days.

-Your doctor might also perform the following tests-:Auscultation (to detect abnormal breath sounds)Chest x-ray.

Nasopharyngeal cultureWhite blood cell differentialOther tests may be done to look at the functions of your heart, kidneys, and liver.

Treatment

Treatment for human-Different types of avian flu virus may cause different

symptoms. Therefore, treatment may vary.

-In general, treatment with the antiviral medication oseltamivir (Tamiflu) or zanamivir (Relenza) may make the disease less severe if you start taking the medicine within 48 hours after your symptoms start.

-Oseltamivir may also be prescribed for persons who live in the same house as those diagnosed with avian flu.

-The virus that causes human avian flu appears to be resistant to the antiviral medicines amantadine and rimantadine. Therefore these medications should not be used if an H5N1 outbreak occurs.

-People with severe infection may need to be placed on a breathing machine.-Experts recommend that persons diagnosed with avian flu be put in isolation.-Doctors recommend that people get an influenza (flu) shot to reduce the chance of an avian flu virus mixing with a human flu virus, which would create a new virus that may easily spread.-The U.S. Food and Drug Administration has approved a vaccine to protect humans from the avian flu. -Experts say the vaccine could be used if the current H5N1 virus starts spreading between people.

Prognosis-The outlook depends on the severity of

infection and the type of avian influenza Virus that caused it. Death is possible

When to Contact a Medical Professional-;

-Call your health care provider if you develop flu-like symptoms within 10 days of handling infected birds or traveling to an area

with a known avian flu outbreak .

Prevention &control in animals

-There no treatment -Just apply biosecurity & treat secondary

bacterial infections if present.-Best doing is that … if appear in a farm

then close it &slaughter then well disposal to carcasses.…

If after isolation we found it (LPAI) in broiler farm then do early marketing.

Vaccines in poultry-Vaccines generally prohibited but we

can use inactivated vaccine. .While in some countries they use NA

vector live vaccine

Biosecurity

Biosecurity

We must take care of that :-

The avian flu virus (H5N1) has been shown to survive in the environment for long periods of time. Infection may be spread simply by touching contaminated surfaces. Birds who were infected with this flu can continue to release the virus in their feces and saliva for as long as 10 days.

Biosecurity-Knowledge of major pathway of spread of HPAI viruses

&their persistence in environment.-Wild live birds &migrated birds must be controlled.

-early detect &report of out breaks. -enhanced biosecurity of poultry farms.

-Hygienic disposal of litters.-Hygienic disposal of dead carcases .

-Visit one farm per day. -Prevent visitors from entry except after doing

decontamination & wearing sterile gloves.-Clean &disinfect vehicles .-Stay out quarantine farms.

Conclusions

Experts are worried that the virus could one day mutate and become easily-human-transmissible. If this occurred, a serious influenza pandemic could occur.

Ref.net. Http//

Conclusion.Hmmm ….while I was talking with Japanese Drs (Dr.Suzuki

(&Dr. Ikuta They told me that there a human vaccine against (H1N1) in Japan is used ..that was during the lecture they were sharing with dr. Madiha & dr . Hany allakany.

- in fact there is another worries from using such pandemic viruses in biological war……. That we all knowing its already occurring alas………. But this will be our next topic insha ALLAH…….

Thank You!!! Acknowledgement Dr. Madiha (prof. dr. of virology )Eng. Raja sheikh Dr. Hany allakany (prof. dr. of poultry dieases)Dr.Ahmed ali sami (prof. dr. of poultry diseases)Dr.Ashraf awad (prof.dr. of poultry diseases)