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Influenza A (H5N1) viruses from pigs, Indonesia.

Nidom CA, Takano R, Yamada S, Sakai-Tagawa Y, Daulay S, Aswadi D, Suzuki T, Suzuki Y, Shinya K, Iwatsuki-Horimoto K, Muramoto Y, Kawaoka Y - Emerging Infect. Dis. (2010)

Bottom Line: Phylogenetic analysis showed that the viruses had been introduced into the pig population in Indonesia on at least 3 occasions.One isolate had acquired the ability to recognize a human-type receptor.No infected pig had influenza-like symptoms, indicating that influenza A (H5N1) viruses can replicate undetected for prolonged periods, facilitating avian virus adaptation to mammalian hosts.

View Article: PubMed Central - PubMed

Affiliation: Airlangga University, Surabaya, East Java, Indonesia.

ABSTRACT
Pigs have long been considered potential intermediate hosts in which avian influenza viruses can adapt to humans. To determine whether this potential exists for pigs in Indonesia, we conducted surveillance during 2005-2009. We found that 52 pigs in 4 provinces were infected during 2005-2007 but not 2008-2009. Phylogenetic analysis showed that the viruses had been introduced into the pig population in Indonesia on at least 3 occasions. One isolate had acquired the ability to recognize a human-type receptor. No infected pig had influenza-like symptoms, indicating that influenza A (H5N1) viruses can replicate undetected for prolonged periods, facilitating avian virus adaptation to mammalian hosts. Our data suggest that pigs are at risk for infection during outbreaks of influenza virus A (H5N1) and can serve as intermediate hosts in which this avian virus can adapt to mammals.

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Related in: MedlinePlus

Phylogenetic relationships of the M (A) and NS (B) genes of H5N1 influenza viruses in Indonesia. All trees were generated by the neighbor-joining method in ClustalW (www.clustal.org). Numbers above or below branches indicate neighbor-joining bootstrap values. Analyses were based on nucleotides 77-955 (879 bp) and 64-789 (726 bp) of the M and NS genes, respectively. Each tree was rooted to A/duck/Shantou/4003/03 for M and NS. Colors indicate swine isolates (blue) and chicken isolates (red) most closely related to swine viruses. Scale bar indicates 0.01 nt substitutions per site. Ck, chicken; Dk, duck; Fl, feline; Gx, Guangxi; HK, Hong Kong; IDN, Indonesia; Qa, quail; ST, Shantou; Sw, swine.
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FA.3: Phylogenetic relationships of the M (A) and NS (B) genes of H5N1 influenza viruses in Indonesia. All trees were generated by the neighbor-joining method in ClustalW (www.clustal.org). Numbers above or below branches indicate neighbor-joining bootstrap values. Analyses were based on nucleotides 77-955 (879 bp) and 64-789 (726 bp) of the M and NS genes, respectively. Each tree was rooted to A/duck/Shantou/4003/03 for M and NS. Colors indicate swine isolates (blue) and chicken isolates (red) most closely related to swine viruses. Scale bar indicates 0.01 nt substitutions per site. Ck, chicken; Dk, duck; Fl, feline; Gx, Guangxi; HK, Hong Kong; IDN, Indonesia; Qa, quail; ST, Shantou; Sw, swine.

Mentions: Phylogenetic analysis of the HA genes of the 13 representative viruses identified the same 3 groups described above. The HA genes of 4 viruses isolated in 2005 (2005 swine group) were placed in clade 2.1.1, and of the remaining 9 swine viruses isolated during 2006–2007, five were classified into the IDN/6/05-like sublineage (2006–07 swine [A] group) and 4 into clade 2.1.3 (2006–07 swine [B] group) (Figure 2, panel A). The most closely related strains of each swine virus group were chicken influenza A (H5N1) viruses: A/chicken/Indonesia/R60/2005 for the 2005 swine group, A/chicken/East Java/UT6016/2006 and A/chicken/East Java/UT6031/2007 for the 2006–07 swine (A) group, and A/chicken/East Java/UT6044/2007 for the 2006–07 swine (B) group. Analyses of the other 7 genes demonstrated that the phylogenetic relationships established for the HA gene were maintained; that is, the swine viruses in each group possessed nearly identical genes, and each group of swine viruses was most closely related to a chicken virus isolated near the site where the swine viruses were collected (Figure 2, panel B; Figure A1, Figure A2, Figure A3). Our results suggest that influenza A (H5N1) viruses were transmitted from avian species to pigs on at least 3 occasions.


Influenza A (H5N1) viruses from pigs, Indonesia.

Nidom CA, Takano R, Yamada S, Sakai-Tagawa Y, Daulay S, Aswadi D, Suzuki T, Suzuki Y, Shinya K, Iwatsuki-Horimoto K, Muramoto Y, Kawaoka Y - Emerging Infect. Dis. (2010)

Phylogenetic relationships of the M (A) and NS (B) genes of H5N1 influenza viruses in Indonesia. All trees were generated by the neighbor-joining method in ClustalW (www.clustal.org). Numbers above or below branches indicate neighbor-joining bootstrap values. Analyses were based on nucleotides 77-955 (879 bp) and 64-789 (726 bp) of the M and NS genes, respectively. Each tree was rooted to A/duck/Shantou/4003/03 for M and NS. Colors indicate swine isolates (blue) and chicken isolates (red) most closely related to swine viruses. Scale bar indicates 0.01 nt substitutions per site. Ck, chicken; Dk, duck; Fl, feline; Gx, Guangxi; HK, Hong Kong; IDN, Indonesia; Qa, quail; ST, Shantou; Sw, swine.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3294999&req=5

FA.3: Phylogenetic relationships of the M (A) and NS (B) genes of H5N1 influenza viruses in Indonesia. All trees were generated by the neighbor-joining method in ClustalW (www.clustal.org). Numbers above or below branches indicate neighbor-joining bootstrap values. Analyses were based on nucleotides 77-955 (879 bp) and 64-789 (726 bp) of the M and NS genes, respectively. Each tree was rooted to A/duck/Shantou/4003/03 for M and NS. Colors indicate swine isolates (blue) and chicken isolates (red) most closely related to swine viruses. Scale bar indicates 0.01 nt substitutions per site. Ck, chicken; Dk, duck; Fl, feline; Gx, Guangxi; HK, Hong Kong; IDN, Indonesia; Qa, quail; ST, Shantou; Sw, swine.
Mentions: Phylogenetic analysis of the HA genes of the 13 representative viruses identified the same 3 groups described above. The HA genes of 4 viruses isolated in 2005 (2005 swine group) were placed in clade 2.1.1, and of the remaining 9 swine viruses isolated during 2006–2007, five were classified into the IDN/6/05-like sublineage (2006–07 swine [A] group) and 4 into clade 2.1.3 (2006–07 swine [B] group) (Figure 2, panel A). The most closely related strains of each swine virus group were chicken influenza A (H5N1) viruses: A/chicken/Indonesia/R60/2005 for the 2005 swine group, A/chicken/East Java/UT6016/2006 and A/chicken/East Java/UT6031/2007 for the 2006–07 swine (A) group, and A/chicken/East Java/UT6044/2007 for the 2006–07 swine (B) group. Analyses of the other 7 genes demonstrated that the phylogenetic relationships established for the HA gene were maintained; that is, the swine viruses in each group possessed nearly identical genes, and each group of swine viruses was most closely related to a chicken virus isolated near the site where the swine viruses were collected (Figure 2, panel B; Figure A1, Figure A2, Figure A3). Our results suggest that influenza A (H5N1) viruses were transmitted from avian species to pigs on at least 3 occasions.

Bottom Line: Phylogenetic analysis showed that the viruses had been introduced into the pig population in Indonesia on at least 3 occasions.One isolate had acquired the ability to recognize a human-type receptor.No infected pig had influenza-like symptoms, indicating that influenza A (H5N1) viruses can replicate undetected for prolonged periods, facilitating avian virus adaptation to mammalian hosts.

View Article: PubMed Central - PubMed

Affiliation: Airlangga University, Surabaya, East Java, Indonesia.

ABSTRACT
Pigs have long been considered potential intermediate hosts in which avian influenza viruses can adapt to humans. To determine whether this potential exists for pigs in Indonesia, we conducted surveillance during 2005-2009. We found that 52 pigs in 4 provinces were infected during 2005-2007 but not 2008-2009. Phylogenetic analysis showed that the viruses had been introduced into the pig population in Indonesia on at least 3 occasions. One isolate had acquired the ability to recognize a human-type receptor. No infected pig had influenza-like symptoms, indicating that influenza A (H5N1) viruses can replicate undetected for prolonged periods, facilitating avian virus adaptation to mammalian hosts. Our data suggest that pigs are at risk for infection during outbreaks of influenza virus A (H5N1) and can serve as intermediate hosts in which this avian virus can adapt to mammals.

Show MeSH
Related in: MedlinePlus