Swine Influenza Swine Influenza (SI), Flu(SI), Flu

Dr. Zuhair Bani IsmailDr. Zuhair Bani Ismail

Jordan University of Science Jordan University of Science and Technologyand Technology

SI In PigsSI In Pigs

Caused by a number of closely related Caused by a number of closely related influenza A virusesinfluenza A viruses change their antigenic structure and create new change their antigenic structure and create new

strains. strains. Each serotype is identified by surface Each serotype is identified by surface

proteins referred to as "H" and "N". proteins referred to as "H" and "N". Three common strains affect pigs described Three common strains affect pigs described

as H1 N1, H1 N2 and H3 N2. as H1 N1, H1 N2 and H3 N2. There are also different strains within these There are also different strains within these

serotypes with differing pathogenicity.serotypes with differing pathogenicity.

SI In PigsSI In Pigs

Short incubation period (12-48 Short incubation period (12-48 hours)hours)

Rapid and dramatic onset. Rapid and dramatic onset. Impossible to maintain a population Impossible to maintain a population

of pigs that is influenza virus free. of pigs that is influenza virus free.

SI In PigsSI In Pigs

Become endemic in large herds. Become endemic in large herds. Intermittent bouts of disease and Intermittent bouts of disease and

infertility.infertility. Different strains may sequentially Different strains may sequentially

infect the herd.infect the herd. Immunity to influenza viruses is often Immunity to influenza viruses is often

short lived (6 months). short lived (6 months). Immunity profile in the breeding herd Immunity profile in the breeding herd

varies considerably with time.varies considerably with time.

SI In PigsSI In Pigs SymptomsSymptoms PigletsPiglets

Clinical signs in suckling pigs unusualClinical signs in suckling pigs unusual Unless disease enter the herd for the first time Unless disease enter the herd for the first time Colostrum provide protectionColostrum provide protection Coughing Coughing PneumoniaPneumonia FeverFever

SowsSows High temperatures which cause abortions High temperatures which cause abortions Widespread coughingWidespread coughing Pneumonia Pneumonia

SI In PigsSI In Pigs

At the beginning of an outbreak in a At the beginning of an outbreak in a herd:herd: Two or three animals may be observed sick Two or three animals may be observed sick

for the first two days, followed by: for the first two days, followed by: Rapid explosive outbreak of inappetenceRapid explosive outbreak of inappetence Very sick pigs. Very sick pigs. Sudden onset of a rapid spreading respiratory Sudden onset of a rapid spreading respiratory

disease with coughing, pneumonia, fevers.disease with coughing, pneumonia, fevers. Reproductive problems Reproductive problems Acute respiratory distress persists over a period Acute respiratory distress persists over a period

of 7-10 days. of 7-10 days.

SI In PigsSI In Pigs

At a herd level the following may be At a herd level the following may be seen: seen: A sudden and rapid onset of acute A sudden and rapid onset of acute

illness in sows. illness in sows. Coughing and pneumonia spreading Coughing and pneumonia spreading

rapidly. rapidly. A return to clinical normality over 7-10 A return to clinical normality over 7-10

days. days. Delayed returns to heat after weaning. Delayed returns to heat after weaning.

SI In PigsSI In Pigs

Increased repeats at 21 days. Increased repeats at 21 days. Increased repeats outside the normal Increased repeats outside the normal

cycle. cycle. Increased numbers of sows coming Increased numbers of sows coming

through not in-pig. through not in-pig. Increased numbers of abortions, Increased numbers of abortions,

particularly late term. particularly late term.

SI In PigsSI In Pigs

Increased numbers of stillbirth rates and Increased numbers of stillbirth rates and slow farrowings. slow farrowings.

Premature farrowings. Premature farrowings. Occasionally an increase in mummified pigs. Occasionally an increase in mummified pigs. During the phases of high temperatures During the phases of high temperatures

other diseases present in the herd may be other diseases present in the herd may be triggered off. triggered off.

A typical example would be an increase in A typical example would be an increase in abortions associated with leptospira abortions associated with leptospira infection. infection.

SI In PigsSI In Pigs

Weaners & Growers Weaners & Growers Acute disease:Acute disease:

Classically the pigs suddenly become Classically the pigs suddenly become prostrate. prostrate.

Breathing heavily. Breathing heavily. Severe coughing. Severe coughing.

SI In PigsSI In Pigs

Weaners & Growers Weaners & Growers Acute disease:Acute disease:

they appear very sickthey appear very sick Most of them survive without treatment Most of them survive without treatment Unless other respiratory disease Unless other respiratory disease

problem present problem present

SI In PigsSI In Pigs

SI causes severe pneumonia on its SI causes severe pneumonia on its own but when it is combined with own but when it is combined with other infections such as other infections such as Actinobacillus pleuropneumonia, Actinobacillus pleuropneumonia, Enzootic pneumonia, and PRRS an Enzootic pneumonia, and PRRS an intractable chronic respiratory intractable chronic respiratory disease syndrome can develop. disease syndrome can develop.

SI In PigsSI In Pigs

Endemic disease:Endemic disease: Virus remains in the herd, affecting Virus remains in the herd, affecting

small groups of pigs often weaners. small groups of pigs often weaners. Responsible for continuing respiratory Responsible for continuing respiratory

diseases with symptoms as in acute diseases with symptoms as in acute disease but less dramatic. disease but less dramatic.

SI In PigsSI In Pigs Contributing factorsContributing factors SI can be introduced by: SI can be introduced by:

Infected animals including people, pigs and birds. Infected animals including people, pigs and birds. Carrier pigs. Carrier pigs. Probably on the wind although this has not been Probably on the wind although this has not been

proved. proved. Birds particularly water fowl, are reservoirs of Birds particularly water fowl, are reservoirs of

infection. infection. Secondary bacterial infections. Secondary bacterial infections. Fluctuating temperatures. Fluctuating temperatures. Stress. Stress. Wet bedding and floor surfaces. Wet bedding and floor surfaces. Poor nutrition. Poor nutrition.

SI In PigsSI In Pigs

DiagnosisDiagnosis Clinical picture of acute respiratory Clinical picture of acute respiratory

disease disease Dramatic onset and rapid spread in the Dramatic onset and rapid spread in the

herd herd Serology testing on affected sows and Serology testing on affected sows and

repeated 2-3 weeks laterrepeated 2-3 weeks later

SI In PigsSI In Pigs

DiagnosisDiagnosis SIV readily grown from nasal and throat SIV readily grown from nasal and throat

swabs and identified using PCR. swabs and identified using PCR. This is often the best approach to This is often the best approach to

confirm the diagnosis. confirm the diagnosis.

SI In PigsSI In Pigs

TreatmentTreatment Animals with acute illness, and raised Animals with acute illness, and raised

temperatures, and increased respiratory rate temperatures, and increased respiratory rate should be treated with broad spectrum should be treated with broad spectrum antibiotics for three days. antibiotics for three days.

Suitable medicines include Suitable medicines include penicillin/streptomycin, long-acting OTC or penicillin/streptomycin, long-acting OTC or synthetic penicillins such as amoxycillin. synthetic penicillins such as amoxycillin.

If the illness is severe then medicate the If the illness is severe then medicate the drinking water with either CTC or OTC at a drinking water with either CTC or OTC at a level of 25g (100% pure) per 1000kg of live level of 25g (100% pure) per 1000kg of live weight per day, for five days. weight per day, for five days.

SI In PigsSI In Pigs

Management control and Management control and preventionprevention It is important to prevent any secondary It is important to prevent any secondary

bacterial infectionsbacterial infections Keep sows within an environmental Keep sows within an environmental

temperature of 20-23ºC temperature of 20-23ºC

SI In PigsSI In Pigs

Management control and Management control and preventionprevention Reduce all possible stress, such as Reduce all possible stress, such as

draughts draughts Maintain dry bedding and floor surfacesMaintain dry bedding and floor surfaces Monitor boars carefully for evidence of Monitor boars carefully for evidence of

illness illness

SI In PigsSI In Pigs

Management control and Management control and preventionprevention Medicate the water with soluble Medicate the water with soluble

vitamins for seven days vitamins for seven days Medicate the feed as described above Medicate the feed as described above

for 2 weeks for 2 weeks If periods of inappetence occur in If periods of inappetence occur in

boars, blood test them twice two weeks boars, blood test them twice two weeks apart to establish a diagnosisapart to establish a diagnosis

SI In PigsSI In Pigs

Management control and preventionManagement control and prevention Because of the possible ways by which the Because of the possible ways by which the

virus may enter the herd it is extremely virus may enter the herd it is extremely difficult to maintain populations free of difficult to maintain populations free of infectionsinfections

In some countries inactivated vaccines are In some countries inactivated vaccines are available and appear to be protective available and appear to be protective

In herds in which the virus periodically In herds in which the virus periodically circulates and causes disease this route circulates and causes disease this route should be exploredshould be explored