during 20102011 , a pertussis outbreak occurred in a suburban town ( town a ) in nobeoka city in miyazaki prefecture , japan . town a has a population of 4,227 persons and an elementary school and junior high school . the first pertussis case ( in a 17-year - old boy ) was reported in september 2010 . from that time , we conducted a laboratory - based active surveillance study in the area until april 2011 , in cooperation with clinics , hospitals , and local health departments . pertussis - suspected cases were defined as an illness with cough lasting for > 2 weeks , and pertussis - confirmed cases were defined as the presence of 1 of the following laboratory findings : a culture - positive result for bordetella species from nps specimens , or a positive result for molecular testing for bordetella species . for molecular testing , we conducted conventional pcr specific for insertion sequence is481 , which is known to detect b. pertussis and b. holmesii , and b. pertussis  specific loop - mediated isothermal amplification assays ( 1012 ) . to further confirm b. holmesii infection , b. holmesii specific real - time pcr specific for the reca gene was also performed as described ( 8) . for confirmed cases of b. holmesii infection , we collected the general information for patients ( clinical symptoms , treatment , contact information , and outcome ) by face - to - face interview or questionnaire . during the pertussis outbreak , we identified 76 suspected pertussis cases . among these suspected cases , 35 cases were confirmed by laboratory testing and involved persons 263 years of age ( median age 13 years ) ; 1 case occurred in a 2-year - old child , 14 in 6- to 12-year - old children , 14 in 1315-year - old children , and 6 in persons > 16 years of age . despite pertussis vaccination rates in childhood of 82.3%92.6% , most ( 80% ) patients were students 612 and 1315 years of age . among the 35 confirmed case - patients , 29 and 6 patients showed b. pertussis and b. holmesii infection , respectively . confirmed cases of b. holmesii infection were observed within the last half of the epidemic curve , i.e. , weeks 112 of 2011 ( figure 1 ) . b ) laboratory - confirmed cases of bordetella pertussis and b. holmesii infection . * as of september 2026 , 2010 . all nps specimens from patients with b. holmesii infection showed a negative result for the b. pertussis loop - mediated isothermal amplification , but showed positive results in the is481 pcr and b. holmesii reca real - time pcr ( table 1 ) . b. holmesii - like organisms were obtained from 5 patients , and these were identified as b. holmesii by reca gene sequencing . patient 6 had been treated with antimicrobial drugs before the culture test , which probably resulted in a culture - negative test result in this patient . real - time pcr confirmed that patient 6 had a low b. holmesii dna load ( threshold cycle 36.6 ) in her nps specimen . all patients experienced paroxysms of coughing without posttussive vomiting , especially at night , and 3 also experienced a whoop ( table 2 ) . no patients experienced any complications , and they were treated mainly with azithromycin , resulting in complete recovery . * all patients had negative results for b. 
 pertussis loop - mediated isothermal amplification and positive results for is481 pcr . detection limit was a ct value of 38.7 , corresponding to 100 fg of dna of b. holmesii atcc51541 . * all patients had a paroxysmal cough and coughed at night ; none had posttussive vomiting . dtp , diphtheria - tetanus - pertussis ; + , positive ; azm , azithromycin ;  , negative ; unk , unknown ; cfpn - pi , cefcapene pivoxil ; grnx , garenoxacin . our surveillance study showed epidemiologic linkage between 5 patients ( patients 26 ) , but not for patient 1 ( figure 2 ) . patient 1 , a student in high school a , had the first case of b. holmesii infection ( probable index case ) . however , his family home was in town a in nobeoka city , and he returned to his home at the end of 2010 and remained there in 2011 . patients 2 , 3 , and 4 were students at the same junior high school ( b ) in town a and were close friends . patient 5 was a teacher at junior high school b and was in charge of patient 4 . patient 6 was a medical practitioner at clinic c , which is 1 of 2 clinics in town a. patients 15 visited clinic c in early january , late february , late february , early march , and late march , 2011 , respectively . the duration of illness in patient 1 did not overlap with that of the other patients , whereas that of patients 26 clearly overlapped . epidemiologic linkage in 6 patients infected with bordetella holmesii during pertussis outbreak , japan , 2011 . patient 3 provided unreliable information about the date of onset and recovery , but the patient s cough lasted for > 1 month . epidemiologic linkage was observed between 5 patients ( patients 26 ) , but not for patient 1 . in the past 16 years , 70 b. holmesii clinical strains have been isolated from human patients in several countries , mainly the united states . all reported cases of b. holmesii infection have been sporadic occurrences . thus , the reservoir of b. holmesii is currently unknown . moreover , whether b. holmesii is transmitted between humans is not known . in this report , we have demonstrated that 5 patients infected with b. holmesii showed epidemiologic linkage . in particular , the fact that 4 of these patients attended the same junior high school suggests that b. holmesii may be transmitted from person to person . a previous report suggested that b. holmesii and b. pertussis may co - circulate in young adults ( 7 ) . however , the relationship between pertussis epidemics and b. holmesii infection is not fully understood . our active surveillance study showed that b. holmesii infection spread concurrently with the b. pertussis epidemic , but that there was no co - infection of b. holmesii and b. pertussis . our observations demonstrate that accurate diagnosis is needed to discriminate between b. holmesii and b. pertussis infections during a pertussis outbreak because symptoms associated with these 2 diseases are similar . in 2012 , previous surveillance studies conducted in the united states and canada have shown low rates ( 0.1%0.3% ) of b. holmesii infection in patients with cough ( 7,8 ) . however , in a recent study , b. holmesii dna was detected in 20% of nps specimens collected from patients in france who had been given a diagnosis of b. pertussis infection ( 14 ) . these surveillance data indicate that b. holmesii infection is present in adolescents and adults , and that the organism is associated with pertussis - like symptoms . however , other causes of viral or bacterial respiratory infection can not be excluded . because of lack of specific diagnostic tools to detect bordetellae , b. holmesii infection may have been underestimated . accurate diagnosis and further studies are required to fully elucidate the nature of b. holmesii infection .
we describe the epidemiology of a pertussis outbreak in japan in 20102011 and bordetella holmesii transmission . 
 six patients were infected ; 4 patients were students and a teacher at the same junior high school . 
 epidemiologic links were found between 5 patients . 
 b. holmesii may have been transmitted from person to person .