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Paper text:
the cases were identified at nepal red cross society ( nrcs ) , central blood transfusion service ( cbts ) , kathmandu , nepal .
information of the subjects such as age and gender was accessed from the standard blood donor questionnaire form of cbts recorded by health professionals from the blood donors .
samples were tested with confidentiality and identified by the sample code number given during the sample collection . ethical approval to conduct the study was taken from cbts . who strategy 2 for surveillance diagnosis of hiv was used for the test of the samples ( 9 ) .
blood samples were tested for hcv using elisa test kits eiagen hcv ab kit ( adaltis , italy ) confirmed with sd bioline hcv ( standard diagnostics , inc .
hcv seropositive cases were tested for hiv , hbv and syphilis with elisa test kits enzygnost anti - hiv  plus ( dade behring , germany ) , enzygnost hbsag 5.0 ( dade behring , germany ) , sd syphilis elisa 3.0 ( standard diagnostics , inc .
, korea ) respectively . the positive test results for hiv , hbv and syphilis were confirmed with rapid immunochromatographic test kits sd bioline hiv- 3.0 ( standard diagnostics , inc .
, korea ) and virucheckhbsag ( orchid biomedical systems , india ) respectively while syphilis was confirmed with the same elisa test kit .
test results with seropositivity for hiv , hbv and syphilis among hcv positive samples were considered to determine the co - infection rate .
among the 139 hcv seropositive cases , eight of them were determined to have co - infections with total co - infection rate of 5.75% ( 95% ci=2.52 - 11.03 ) .
co - infection rate of hiv among hcv was 3.59% , hbv among hcv was 0.71% and syphilis among hcv was 1.43% ( table 1 ) .
all the co - infection cases were male though 11 hcv seropositive females were included in the study .
hiv / hcv co - infection was seen in the age group between 2150 years .
hbv / hcv co - infection in the age group 3140 years and syphilis / hcv in the age group 2130 years . 
 
prevalence of hiv , hbv and syphilis co - infection among hcv cases indicates that the infections could be transmitted simultaneously due to their common modes of transmission .
hcv is more commonly transmitted among idus and the co - infection of hiv , hbv and syphilis with hcv can be due to transmission modes such as sharing of needles or unsafe sexual transmission among such risk groups .
hiv / hcv was the most common co - infection followed by syphilis / hcv and hbv / hcv .
prevalence of higher hiv / hcv co - infection in this study can be due to the practice of injecting drug use as many idus who become infected with hiv are already infected with hcv .
hiv / hcv co - infection determined is lower than the reported co - infection rate of 10.8% with hcv and hiv ( 4 ) .
co - infection rate of hiv in hcv estimated is similar to the reported rate of hcv co - infection in hiv patients in north india ( 2.43% ) and 2.2% reported in south india ( 10 , 11 ) .
hbv / hcv co - infection is lower than the hcv / hbv co - infection rate of 1.67% reported in nepalese blood donors ( 5 ) .
lower co - infections rate in this study is due to the low - risk group of population ( healthy looking blood donors ) considered ; decreasing prevalence of transfusion transmissible infections ( 3 ) .
higher hiv / hcv co - infection indicates hiv risks associated with the injecting drugs users who are usually infected with hcv .
prevalence of co - infections observed in the study in only males indicates indulgence of such gender groups in unsafe practices that could have transmitted the multiple infections .
monitoring of co - infections is necessary to commence immediate treatment of the cases besides prevention of transfusion associated risks with such blood donors .
co - infection of hiv , hbv and syphilis with hcv is prevalent in the blood donors of kathmandu , nepal .
further investigations can be carried out with larger sample size and in high risk groups with other infections sharing common modes of transmission to estimate the co - infections in the general population of the country .
the authors have not received any funding or benefits from industry or elsewhere to conduct this study .
backgroundhiv , hbv , syphilis and hcv share common modes of transmission.objectivethe study was aimed to determine the co - infection rate of hiv , hbv and syphilis among hcv seropositive identified blood donors.methodsthe study was conducted on blood samples screened as hcv seropositive at nepal red cross society , central blood transfusion service , kathmandu , nepal . 
 hcv seropositive samples were further tested for hiv , hbv and syphilis.resultseight co - infections were observed in 139 hcv seropositives with total co - infection rate of 5.75% ( 95% ci=2.52 - 11.03).conclusionco - infection of hiv , hbv and syphilis with hcv is prevalent in the healthy looking blood donors of kathmandu , nepal .