on february 15 , 2014 , a 50-year - old man , owner of a small farm in changchun , jilin province , experienced an isolated fever ( axillary temperature 38.3c ) . the man sought medical care that day at jilin university third hospital and returned to the hospital on february 16 , 17 , and 19 with ongoing fever . radiographic imaging showed evidence of pneumonia ; he received intravenous administration of azithromycin and xiyanping , a traditional chinese medicine . on february 19 , the man sought care at jilin university first hospital , where throat swab samples were taken . the same day , testing of the samples at the local and provincial centers for disease control and prevention yielded positive results for influenza a(h7n9 ) virus by real - time reverse transcription pcr ( rt - pcr ) ; china cdc confirmed results the next day . treatment with oseltamivir ( 150 mg 2/d ) and methylprednisolone ( 80 mg 2/d ) was initiated , and oxygen was administered by nasal cannula . the man denied exposure to poultry other than on his farm , including to poultry on other farms or in lpms . he reported no contact with persons who had similar symptoms before onset of his illness . as part of the case investigation , 68 close contacts of the case - patient were monitored for 7 days ; 1 contact had influenza - like illness . throat swab specimens were collected from this person on days 2 and 3 after symptom onset and tested for influenza a(h7n9 ) by using real - time rt - pcr ; results were negative . the virus from the case - patient s specimens was isolated in egg culture and designated a / jilin/10117/2014 ( h7n9 ) ( full sequence available from gisaid , accession no . epi_isl_161665 ) . the isolate s 8 genes were similar to those of the virus a / anhui/ 02/2013 ( h7n9 ) ( gisaid accession no . epi_isl_141190 ) ; nucleotide / amino acid homology was 99.5%/99.6% for hemagglutinin , 99.2%/98.9% for neuraminidase , 99.3%/99.7% for polybasic 1 , 96.4%/98.9% for polybasic 2 , 97.9%/99.6% for polymerase acidic , 99.7%/99.6% for nucleoprotein , 97.7%/100.0% for matrix protein , and 99.5%/99.1% for nonstructural protein . during august 2013february 2014 , the case - patient had introduced 7 groups of birds to his farm , totaling 1,100 birds from 8 source farms ( figure 2 ) . the birds were turkeys , guinea fowl ( numida meleagris ) , black - bone silkie chickens ( gallus gallus domesticus ) , local chickens , and a goose . none of the birds received avian influenza vaccines on the case - patient s farm ; previous vaccination histories were unknown . birds commingled in an egg production warehouse ( figure 3 ) maintained by the case - patient and by 2 farmers hired in early january 2014 . the warehouse was seldom cleaned and never disinfected . the case - patient cared for the birds daily and did not use personal protective equipment . timeline of introduction of new birds to the farm of the case - patient with influenza a(h7n9 ) virus infection in jilin province , china , 20132014 . dates of illnesses and deaths among bird flock on farm , the case - patient s symptom onset , and confirmed testing results are indicated . internal ( top ) and external views of the warehouse where poultry were housed on the farm of the case - patient who had confirmed influenza a(h7n9 ) virus infection in february 2014 in jilin province , china . , a group of 280 silkie chickens and guinea fowl was introduced to the warehouse and subsequently exhibited signs of illness ; many of these birds died during the next 3 months . a veterinarian reportedly diagnosed air sacculitis and enteritis ; testing for influenza a was not performed . by january 2014 , all but 4 silkie chickens and 40 guinea fowl had died . more birds were added on february 3 , but no further illness was noted until 2 additional flocks , totaling 290 birds , arrived on february 10 and 12 . widespread illness then occurred among the birds , including respiratory and eye secretions , wheezing , and death ; > 100 birds had died by february 15 , when the case - patient s symptoms began . the changchun prefectural bureau of agriculture performed necropsies and attributed these deaths to a mixed infection of fowlpox and colibacillosis . investigation and sampling at the case - patient s farm and related suppliers were conducted by local , provincial , and national cdcs . public health laboratories tested 84 poultry and environmental specimens collected from the farm ( table ) ; 19 samples were positive by real - time rt - pcr for both influenza a(h7n9 ) and a(h9n2 ) , 1 was positive only for h7n9 , and 3 were positive only for h9n2 . a total of 374 samples were collected from the 8 source farms , the farms and transport vehicles of the 2 distributors who delivered chickens to the case - patient s farm , and 56 other local farms . four specimens from 1 distributor tested positive for influenza a h9 by rt - pcr ; neuraminidase subtyping was not performed on these specimens . * one oropharyngeal swab sample from a goose and 1 oropharyngeal swab from a turkey were included in the specimens from case - patient poultry farm ; both samples were positive for influenza a(h7n9 ) and a(h9n2 ) . distributors bought poultry from companies or local farmers ( source farms ) and then sold the poultry to others , including the case - patient . samples were taken from transport vehicles and farms of 2 distributors who transported the chickens to the case - patient s farm . all positive specimens were from a single distributor : 3 from his transport vehicle and 1 from his farm . eight farms that supplied the birds to the case - patient ( source farms ) and 56 other farms located in the villages of the case - patient and source farms . we describe a human case of influenza a(h7n9 ) virus infection epidemiologically linked to a poultry farm from which samples tested positive for h7n9 and h9n2 viruses . previous reports of human subtype h7n9 virus infections in mainland china identified a poultry - related exposure for 84% of case - patients , 77% of which were linked to lpms , but none were linked to farms ( china cdc , unpub . almost all positive samples have been from lpms ; h7n9 virus was initially isolated from farms in guangdong province in southern china in mid - march 2014 ( 2 ) . samples collected from a farm in zhejiang province were also positive for influenza a(h7n9 ) virus by real - time rt - pcr , but human cases were not epidemiologically linked to this farm ( 3 ) . unlike avian influenza a(h5n1 ) virus , which frequently causes severe disease and death in poultry , influenza a(h7n9 ) virus is a low pathogenicity virus and has not been observed to cause substantial deaths in avian species . under experimental conditions , birds exhibited no clinical disease after h7n9 virus challenge , although chickens and quail shed high levels of virus ( 4 ) . the poultry on this case - patient s farm were co - infected with other pathogens , and many died in the week preceding the case - patient s illness . the introduction of even a low pathogenicity virus into a flock already challenged with other pathogens likely contributed to the rates of illness and deaths . this case report underscores the importance of highly sensitive assays in detecting h7n9 virus in poultry and their surrounding environments . the virus was detected in a substantial proportion of specimens on the case - patient s farm ( 20/84 , 24% ) ; in addition , we found that 95% ( 19/20 ) of specimens positive for h7n9 virus were also positive for h9n2 virus . the h7n9 virus possesses internal gene cassettes from poultry h9n2 virus , another low pathogenicity virus that circulates widely in poultry in asia ( 3,5,6 ) . co - circulation of h7n9 and h9n2 viruses was reported in lbms in hangzhou but not on farms ( 3 ) . public health measures taken to contain the outbreak of h7n9 virus infection have thus far focused on lpms ( 714 ) , but our findings suggest that small - scale farms may be another source . inadequate cleaning and disinfecting , a lack of personal protective equipment , and the comingling of bird species found on this farm are common in small - scale poultry farms .
we report on a case of human infection with influenza a(h7n9 ) virus in jilin province in northeastern china . 
 this case was associated with a poultry farm rather than a live bird market , which may point to a new focus for public health surveillance and interventions in this evolving outbreak .