Influenza
Conditions
Brief summary
This study seeks to determine the incidence and transmission of avian influenza viruses in humans exposed to poultry. Enrolled subjects will be selected from five different rural areas (villages) in the Nile delta region in Egypt where poultry are commonly raised. From those study sites, 2400 healthy subjects will be monitored for 6 years with annual follow up visits to measure sero-prevalence and exposure variables, and more importantly, biweekly or weekly visits to measure incidence of infection, measure secondary transmission rates, monitor symptoms, and assess immunological response. Primary Objectives: * To estimate the incidence of avian influenza (AI) in poultry-exposed human populations. * To estimate sero-prevalent of AI in poultry-exposed human populations. * To investigate potential risk factors associated with AI human infections in poultry-exposed individuals. * To investigate secondary infection risk for household contacts. Secondary Objectives: * To characterize the antigenic and genetic makeup of AI viruses infecting humans. * To monitor the pathogenicity and disease severity of AI viruses causing human infections and the associated immune response. * To investigate the serologic response following confirmed influenza virus infection.
Detailed description
All residents of a household will be invited to participate. After study enrollment, participants will complete a questionnaire to collect data on the demographics and health status of the subjects and the poultry kept at the household. A 3-ml blood sample will be obtained from each subject for serological testing. Field nurses or physicians will visit each household biweekly (October through March) or weekly (April through September) to determine if any subject has influenza-like illness (ILI), defined according to Centers for Disease Control (CDC) criteria as having measured fever of ≥38ºC. and cough and/or sore throat. Subjects with confirmed ILI (index case) will provide two nasal swabs for a point-of-care rapid influenza A test and PCR. For those who test positive for influenza A by rapid test or PCR on nasal swab (day 1), two 3-ml blood samples will be obtained. In addition, nasal washes, throat swabs, and blood samples will be obtained from all household contacts. Cloacal swabs will also be collected from the poultry in the household on day 1. The index case and household contacts will be re-sampled by nasal wash and throat swab on days 3, 6, 9 and 14 post initial diagnosis data, and an additional 3-ml blood sample will be obtained on day 14 for serological testing. Household contacts who report ILI symptoms during follow-up visits to the index case will then be followed with the same follow-up regimen as the original index case. At annual follow-up and final visits, questionnaire data will be updated if needed, and a 3-ml blood sample will be obtained from each subject for serological testing.
Interventions
OTHERQuestionnaire
Once at enrollment, subjects will complete an enrollment question to capture poultry exposure and other demographic information. Information will be updated if needed at annual follow-up and at final visits.
OTHERBlood sample
Participants will have a 3-mo blood sample drawn for serological testing at enrollment, and at annual follow-up and final visits. For subjects who test positive for influenza A by rapid test or PCR (index case) on nasal swab at the biweekly or weekly visits, two 3-ml blood samples will be obtained from the index case on day 1 for serological testing for antibodies against avian influenza viruses and for isolating and studying PBMCs. Blood samples will also be obtained on day 1 from all household contacts of the index case. Additional 3-ml blood samples will be obtained on day 14 for serology and PBMCs.
OTHERNasal wash
Nasal washes will be obtained from subjects who test positive for influenza A by rapid test or PCR on nasal swab (index case). Nasal washes will also be obtained from all household contacts of the index case. The index case and household contacts will be re-sampled on days 3, 6, 9 and 14 post initial diagnosis date.
OTHERThroat swab
Throat swabs will be obtained from subjects who test positive for influenza A by rapid test or PCR on nasal swab (index case). Throat swabs will also be obtained from all household contacts of the index case. The index case and household contacts will be re-sampled on days 3, 6, 9 and 14 post initial diagnosis date.
Sponsors
Department of Health and Human Services
Human Link
St. Jude Children's Research Hospital
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
2 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Poultry-exposed individuals with poultry in the household willing to participate by signing a consent or assent form as appropriate for age, completing the study questionnaire, and permitting the withdrawal of blood, nasal washes, nasal swabs, and throat swabs.
Exclusion criteria
* Any known immunosuppressive condition or immune deficiency disease (including HIV infection), or ongoing receipt of any immunosuppressive therapy. (Note that we have chosen to exclude such populations because of their increased risk of acquiring infections, they are relatively few, and are not representative of a national sample.) * Terminally ill individuals. * Children who are less than 2 years old when baseline enrollment is performed.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of avian influenza (AI) in poultry-exposed populations | Up to 6 years | New cases of avian influenza (AI) in poultry-exposed human populations will be detected using throat and nasal swabs and nasal washes obtained from subjects using rapid tests and molecular techniques. |
| Sero-prevalence rates of infection with AI viruses | Up to 6 years | Prevalence rates will be measured by the presence of antibodies against AI viruses subtypes using a micro-neutralization assay. Incidence rates will be assessed based on molecular detection of AI infection annually with 95% confidence intervals. Risk or protective factors correlated with infection will be measured using the baseline enrollment questionnaire. |
| Risk factors associated with AI human infections in poultry-exposed individuals | Up to 6 years | A questionnaire will be used to collect specific occupational, environmental, and behavioral risk factors. These will be correlated to sero-prevalence and incidence of AI infections. |
| Secondary infection risk for household contacts | Up to 6 years | Throat and nasal swabs, blood, and nasal washes will be obtained from household contacts of poultry-exposed individuals with a confirmed influenza A infection. These will be tested for the presence of influenza A viruses or antibodies against influenza A viruses. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Pathogenicity and disease severity of AI viruses causing human infections and the associated immune response | Up to 6 years | Data will be collected on disease pathogenicity and severity of symptoms from subjects reporting ILI and blood samples will be obtained to isolate and study peripheral blood mononuclear cells (PBMCs). PBMCs will be used to study innate and adaptive cell phenotyping by flow cytometry and functional assays that will be read out by flow cytometry and ELISPOT. |
| Serologic response following confirmed influenza virus infection | Up to 6 years | Antibodies will be measured in acute and convalescent sera of confirmed influenza cases. |
| Antigenic and genetic makeup of AI viruses infecting humans | Up to 6 years | PCR, sequencing, culture and serological techniques will be used to characterize these viruses. |
Countries
Egypt
Outcome results
None listed