Swine Influenza (SI), Flu Dr. Zuhair Bani Ismail Jordan University of Science and Technology

SI In Pigs Caused by a number of closely related influenza A viruses Caused by a number of closely related influenza A viruses change their antigenic structure and create new strains. change their antigenic structure and create new strains. Each serotype is identified by surface proteins referred to as "H" and "N". Each serotype is identified by surface proteins referred to as "H" and "N". Three common strains affect pigs described as H1 N1, H1 N2 and H3 N2. Three common strains affect pigs described as H1 N1, H1 N2 and H3 N2. There are also different strains within these serotypes with differing pathogenicity. There are also different strains within these serotypes with differing pathogenicity.

SI In Pigs Short incubation period (12-48 hours) Short incubation period (12-48 hours) Rapid and dramatic onset. Rapid and dramatic onset. Impossible to maintain a population of pigs that is influenza virus free. Impossible to maintain a population of pigs that is influenza virus free.

SI In Pigs Become endemic in large herds. Become endemic in large herds. Intermittent bouts of disease and infertility. Intermittent bouts of disease and infertility. Different strains may sequentially infect the herd. Different strains may sequentially infect the herd. Immunity to influenza viruses is often short lived (6 months). Immunity to influenza viruses is often short lived (6 months). Immunity profile in the breeding herd varies considerably with time. Immunity profile in the breeding herd varies considerably with time.

SI In Pigs Symptoms Symptoms Piglets Piglets Clinical signs in suckling pigs unusual Clinical 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 protection Colostrum provide protection Coughing Coughing Pneumonia Pneumonia Fever Fever Sows Sows High temperatures which cause abortions High temperatures which cause abortions Widespread coughing Widespread coughing Pneumonia Pneumonia

SI In Pigs At the beginning of an outbreak in a herd: At the beginning of an outbreak in a herd: Two or three animals may be observed sick for the first two days, followed by: Two or three animals may be observed sick for the first two days, followed by: Rapid explosive outbreak of inappetence Rapid explosive outbreak of inappetence Very sick pigs. Very sick pigs. Sudden onset of a rapid spreading respiratory disease with coughing, pneumonia, fevers. Sudden onset of a rapid spreading respiratory disease with coughing, pneumonia, fevers. Reproductive problems Reproductive problems Acute respiratory distress persists over a period of 7-10 days. Acute respiratory distress persists over a period of 7-10 days.

SI In Pigs At a herd level the following may be seen: At a herd level the following may be seen: A sudden and rapid onset of acute illness in sows. A sudden and rapid onset of acute illness in sows. Coughing and pneumonia spreading rapidly. Coughing and pneumonia spreading rapidly. A return to clinical normality over 7-10 days. A return to clinical normality over 7-10 days. Delayed returns to heat after weaning. Delayed returns to heat after weaning.

SI In Pigs Increased repeats at 21 days. Increased repeats at 21 days. Increased repeats outside the normal cycle. Increased repeats outside the normal cycle. Increased numbers of sows coming through not in- pig. Increased numbers of sows coming through not in- pig. Increased numbers of abortions, particularly late term. Increased numbers of abortions, particularly late term.

SI In Pigs Increased numbers of stillbirth rates and slow farrowings. Increased numbers of stillbirth rates and slow farrowings. Premature farrowings. Premature farrowings. Occasionally an increase in mummified pigs. Occasionally an increase in mummified pigs. During the phases of high temperatures other diseases present in the herd may be triggered off. During the phases of high temperatures other diseases present in the herd may be triggered off. A typical example would be an increase in abortions associated with leptospira infection. A typical example would be an increase in abortions associated with leptospira infection.

SI In Pigs Weaners & Growers Weaners & Growers Acute disease: Acute disease: Classically the pigs suddenly become prostrate. Classically the pigs suddenly become prostrate. Breathing heavily. Breathing heavily. Severe coughing. Severe coughing.

SI In Pigs Weaners & Growers Weaners & Growers Acute disease: Acute disease: they appear very sick they appear very sick Most of them survive without treatment Most of them survive without treatment Unless other respiratory disease problem present Unless other respiratory disease problem present

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

SI In Pigs Endemic disease: Endemic disease: Virus remains in the herd, affecting small groups of pigs often weaners. Virus remains in the herd, affecting small groups of pigs often weaners. Responsible for continuing respiratory diseases with symptoms as in acute disease but less dramatic. Responsible for continuing respiratory diseases with symptoms as in acute disease but less dramatic.

SI In Pigs Contributing factors Contributing 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 proved. Probably on the wind although this has not been proved. Birds particularly water fowl, are reservoirs of infection. Birds particularly water fowl, are reservoirs of 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 Pigs Diagnosis Diagnosis Clinical picture of acute respiratory disease Clinical picture of acute respiratory disease Dramatic onset and rapid spread in the herd Dramatic onset and rapid spread in the herd Serology testing on affected sows and repeated 2-3 weeks later Serology testing on affected sows and repeated 2-3 weeks later

SI In Pigs Diagnosis Diagnosis SIV readily grown from nasal and throat swabs and identified using PCR. SIV readily grown from nasal and throat swabs and identified using PCR. This is often the best approach to confirm the diagnosis. This is often the best approach to confirm the diagnosis.

SI In Pigs Treatment Treatment Animals with acute illness, and raised temperatures, and increased respiratory rate should be treated with broad spectrum antibiotics for three days. Animals with acute illness, and raised temperatures, and increased respiratory rate should be treated with broad spectrum antibiotics for three days. Suitable medicines include penicillin/streptomycin, long- acting OTC or synthetic penicillins such as amoxycillin. Suitable medicines include penicillin/streptomycin, long- acting OTC or synthetic penicillins such as amoxycillin. If the illness is severe then medicate the drinking water with either CTC or OTC at a level of 25g (100% pure) per 1000kg of live weight per day, for five days. If the illness is severe then medicate the drinking water with either CTC or OTC at a level of 25g (100% pure) per 1000kg of live weight per day, for five days.

SI In Pigs Management control and prevention Management control and prevention It is important to prevent any secondary bacterial infections It is important to prevent any secondary bacterial infections Keep sows within an environmental temperature of º C Keep sows within an environmental temperature of º C

SI In Pigs Management control and prevention Management control and prevention Reduce all possible stress, such as draughts Reduce all possible stress, such as draughts Maintain dry bedding and floor surfaces Maintain dry bedding and floor surfaces Monitor boars carefully for evidence of illness Monitor boars carefully for evidence of illness

SI In Pigs Management control and prevention Management control and prevention Medicate the water with soluble vitamins for seven days Medicate the water with soluble vitamins for seven days Medicate the feed as described above for 2 weeks Medicate the feed as described above for 2 weeks If periods of inappetence occur in boars, blood test them twice two weeks apart to establish a diagnosis If periods of inappetence occur in boars, blood test them twice two weeks apart to establish a diagnosis

SI In Pigs Management control and prevention Management control and prevention Because of the possible ways by which the virus may enter the herd it is extremely difficult to maintain populations free of infections Because of the possible ways by which the virus may enter the herd it is extremely difficult to maintain populations free of infections In some countries inactivated vaccines are available and appear to be protective In some countries inactivated vaccines are available and appear to be protective In herds in which the virus periodically circulates and causes disease this route should be explored In herds in which the virus periodically circulates and causes disease this route should be explored