Lassa Virus InfectionNCT03783143
Prevalence and Incidence of Lassa Virus Infection in Southern Mali
An observational study of Lassa Virus Infection, run by National Institute of Allergy and Infectious Diseases (NIAID) at 1 site in Mali.
Trial summary
Background: The disease Lassa fever mostly affects people in Western Africa. It is very similar to other diseases that cause fever, like malaria and yellow fever. People get Lassa fever from mice infected with Lassa virus. It can also be spread from body fluids of people with the disease. Read more about this study
- Who is it for?
- Ages 6 months to 110 years
- Conditions the study is for
- Lassa Virus Infection
- How many people
- 8,524 participants
- Where
- 1 siteMali
- Study dates
- 4 Dec 2020to 25 Jul 2024
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 6 months to 110 years
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Individuals will be randomly identified from village census lists, and a member of the study team will contact the individual by phone or in person about potential participation in the study. In accordance with cultural practices, the individual s entire household will be invited to participate
Who may be able to join
- Age greater than or equal to 6 months to 99 years.
- Resident of one of the study sites for at least 3 months.
- Able to provide informed consent.
- Agrees to allow storage of samples for future research.
- Additional inclusion criteria for the cross-sectional study (study 1):
- 1. No plans to relocate before the study end date.
Show all 13Show fewer
- Additional inclusion criteria for the clinic-based study (study 2):
- Has fever (temperature greater than or equal to 38 degree celcius), or has had antecedent of fever for at least 2 consecutive days at the time of screening.
- One or more of the following:
- Excluded typhoid fever and and has at least 1 of the following symptoms: chest pain, sore throat, headache, muscle pain,vomiting, and diarrhea.
- Shows bleeding or facial edema.
- Does not respond to anti-malarials or antibiotics after 2 days of treatment.
- Had contact with a confirmed LF case within the last 3 weeks.
Who cannot join
- General exclusion criteria:
- Any condition that, in the opinion of the investigator, contraindicates participation in this study, including conditions that could hinder compliance or that could place participants or study staff at increased risk.
- Pregnancy.
- Additional exclusion criteria for the clinic-based study (study 2):
- 1. Signs or symptoms of fever-associated conditions other than LF, such as urinary tract infection, or any other infection that may cause fever.
- Co-enrollment guidelines: Participants may be co-enrolled in other studies; however, study staff should be notified of co-enrollment
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Serosurvey for Prevalence and Incidence of Lassa Virus Infection in Southern Mali
Background:
The disease Lassa fever mostly affects people in Western Africa. It is very similar to other diseases that cause fever, like malaria and yellow fever. People get Lassa fever from mice infected with Lassa virus. It can also be spread from body fluids of people with the disease. Researchers want to learn more about this virus in Mali so they can develop better tools to diagnose and prevent it.
Read more
Objective:
To find out how many people in certain areas of southern Mali have ever had Lassa fever and count how many people get the disease every year.
Eligibility:
People ages 6 months to 99 years who live in certain areas of Mali
Design:
Women who are could become pregnant will have a urine pregnancy test at each visit.
Participants will be asked questions about their age, if they have ever had a fever, and if they have ever seen mice in or around their home. This will take about 20 minutes.
Participants will give a blood sample using a needle in a vein in the arm. Young children will give it by pricking a finger or heel with a needle.
Patients with a fever illness will have a medical history and physical exam. They will give blood and nasal swabs 3 times over 21 days.
Participants may be asked to come back 1 time each year for up to 3 more years to take another sample of blood and answer more questions.
Read the detailed description
In West Africa, as many as 300,000 people are infected annually with Lassa virus (LASV), resulting in approximately 5,000 deaths. Most commonly, human infection comes from contact with infected rodent hosts (Mastomys natalensis), or ingestion or inhalation of virus-laden particles. Person-to-person transmission is also well documented and can cause outbreaks, especially in nosocomial settings. Infection in pregnancy, especially the third trimester, is particularly severe, with maternal mortality rates estimated at 20% and fetal mortality rates nearing 100%. A survey of rodents captured in the village of Soromba (rural commune of Sibirila, district of Bougouni, Mali) found that 25% of M. natalensis had evidence of LASV infection. A 2015 study of LASV infection in the human populations of this region showed seroprevalence of 33.2% and annual incidence rate of 6.3% in 2016.
The purpose of this serosurvey study is to determine the prevalence and incidence of human exposure to LASV in the administrative districts of Bougouni, Yanfolila, and Kolondieba in southern Mali. The study involves 2 separate sub-studies. Study 1 is a cross-sectional serosurvey of residents of the general population selected from a census. The study will follow up to 500 participants at each of 4 study sites (Fakola, Bamba, Filamana, and Guelelinkoro). Participants will be asked to give blood samples at baseline and annually for up to 3 years. Study 2 is a clinic-based serosurvey conducted at local health centers following up to 500 participants per year at each of the 4 study sites (Fakola, Bamba, Filamana, and Guelelinkoro). Patients who report with febrile illness suggestive of Lassa fever will be asked to give blood and nasal swab samples, then return for follow-up visits 5 and 21 days later for clinical consultation and additional blood and swab collection.
All participants will be provided with free medical treatment according to local standard of care as needed for the duration of the study. They will be followed passively between study visits and instructed to report to their local health center if they have a fever. Study visits will be conducted through a common end date, up to 3 years.
Blood and nasal swab samples will be used to identify history of or current LASV infection and for exploratory studies into the biochemistry and pathophysiology of LASV infection. Elucidating the prevalence of LASV infection in the populations of southern Mali may help Malian authorities improve surveillance, and additional research may help develop diagnostics and treatment.
- Conditions
- Lassa Virus Infection
- Keywords
- Febrile, Human, Lassa Fever, Seroconversion, Natural History
- Medical subject headings
- Lassa Fever, Fever, HIV Seropositivity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Clinical Cohort | This study population will consist of patient volunteers that visit one of our clinical sites with an undiagnosed febrile illness. | |
| Cross-sectional Cohort | This study population will consist of patient volunteers that visit one of our clinical sites with an undiagnosed febrile illness. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Determine the prevalence and
Determine the prevalence and annual incidence of seroconversion to LASV infection in the general population around each study site in the LASV-endemic area of southern Mali
Measured: At time of study start
Determine the incidence of LF in febrile patients attending health centers in southern Mali
Determine the incidence of LF in febrile patients attending health centers in southern Mali over 3 years.
Measured: Over 3 years
Secondary outcomes (1)
Determine the biological, clinical, and virologic parameters of LASV-Soromba infection in study participants with LF.
Determine the biological, clinical, and virologic parameters of LASV-Soromba infection in study participants with LF.
Measured: At time of study start.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Dec 2018
- Study start4 Dec 2020
- Primary completion25 Jul 2024
- Study completion25 Jul 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Lassa Virus InfectionStudies of the same condition, open and under way.
- More trials run by National Institute of Allergy and Infectious Diseases (NIAID)The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 8,524 participants (actual)
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
- Responsible party
- Sponsor
- Investigators
- Heinrich U Feldmann, M.D., Principal investigator, National Institute of Allergy and Infectious Diseases (NIAID)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03783143
- Sponsor's protocol ID
- 999919029
- Other IDs
- 19-I-N029
- Status last verified
- 14 Jul 2026
- First submitted
- 19 Dec 2018
- Last updated
- 28 Aug 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Although samples were collected prospectively all testing is performed retrospectively. Our agreement with the local health centers is to inform them of the overall results of the study and their region in particular. We do not plan to inform individuals.
Study at a glance
From the registry record, last updated by the sponsor on 28 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Serosurvey for Prevalence and Incidence of Lassa Virus Infection in Southern Mali
- ClinicalTrials.gov ID
- NCT03783143
- Acronym / sponsor ID
- 999919029
- Conditions
- Lassa Virus Infection
- Keywords
- Febrile, Human, Lassa Fever, Seroconversion, Natural History
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 8,524 participants (actual)
- Lead sponsor
- National Institute of Allergy and Infectious Diseases (NIAID)US National Institutes of Health
- Study start
- 4 Dec 2020 (actual)
- Primary completion
- 25 Jul 2024 (actual)
- Study completion
- 25 Jul 2024 (actual)
- First posted
- 20 Dec 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Background:
The disease Lassa fever mostly affects people in Western Africa. It is very similar to other diseases that cause fever, like malaria and yellow fever. People get Lassa fever from mice infected with Lassa virus. It can also be spread from body fluids of people with the disease. Researchers want to learn more about this virus in Mali so they can develop better tools to diagnose and prevent it.
Objective:
To find out how many people in certain areas of southern Mali have ever had Lassa fever and count how many people get the disease every year.
Eligibility:
People ages 6 months to 99 years who live in certain areas of Mali
Design:
Women who are could become pregnant will have a urine pregnancy test at each visit.
Participants will be asked questions about their age, if they have ever had a fever, and if they have ever seen mice in or around their home. This will take about 20 minutes.
Participants will give a blood sample using a needle in a vein in the arm. Young children will give it by pricking a finger or heel with a needle.
Patients with a fever illness will have a medical history and physical exam. They will give blood and nasal swabs 3 times over 21 days.
Participants may be asked to come back 1 time each year for up to 3 more years to take another sample of blood and answer more questions.
Detailed description
In West Africa, as many as 300,000 people are infected annually with Lassa virus (LASV), resulting in approximately 5,000 deaths. Most commonly, human infection comes from contact with infected rodent hosts (Mastomys natalensis), or ingestion or inhalation of virus-laden particles. Person-to-person transmission is also well documented and can cause outbreaks, especially in nosocomial settings. Infection in pregnancy, especially the third trimester, is particularly severe, with maternal mortality rates estimated at 20% and fetal mortality rates nearing 100%. A survey of rodents captured in the village of Soromba (rural commune of Sibirila, district of Bougouni, Mali) found that 25% of M. natalensis had evidence of LASV infection. A 2015 study of LASV infection in the human populations of this region showed seroprevalence of 33.2% and annual incidence rate of 6.3% in 2016.
The purpose of this serosurvey study is to determine the prevalence and incidence of human exposure to LASV in the administrative districts of Bougouni, Yanfolila, and Kolondieba in southern Mali. The study involves 2 separate sub-studies. Study 1 is a cross-sectional serosurvey of residents of the general population selected from a census. The study will follow up to 500 participants at each of 4 study sites (Fakola, Bamba, Filamana, and Guelelinkoro). Participants will be asked to give blood samples at baseline and annually for up to 3 years. Study 2 is a clinic-based serosurvey conducted at local health centers following up to 500 participants per year at each of the 4 study sites (Fakola, Bamba, Filamana, and Guelelinkoro). Patients who report with febrile illness suggestive of Lassa fever will be asked to give blood and nasal swab samples, then return for follow-up visits 5 and 21 days later for clinical consultation and additional blood and swab collection.
All participants will be provided with free medical treatment according to local standard of care as needed for the duration of the study. They will be followed passively between study visits and instructed to report to their local health center if they have a fever. Study visits will be conducted through a common end date, up to 3 years.
Blood and nasal swab samples will be used to identify history of or current LASV infection and for exploratory studies into the biochemistry and pathophysiology of LASV infection. Elucidating the prevalence of LASV infection in the populations of southern Mali may help Malian authorities improve surveillance, and additional research may help develop diagnostics and treatment.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Clinical Cohort | – | –This study population will consist of patient volunteers that visit one of our clinical sites with an undiagnosed febrile illness. |
| Cross-sectional Cohort | – | –This study population will consist of patient volunteers that visit one of our clinical sites with an undiagnosed febrile illness. |
Who may qualify
- Ages
- 6 months to 110 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Individuals will be randomly identified from village census lists, and a member of the study team will contact the individual by phone or in person about potential participation in the study. In accordance with cultural practices, the individual s entire household will be invited to participate
Key inclusion criteria (13 listed)
- 1. No plans to relocate before the study end date.
- Has fever (temperature greater than or equal to 38 degree celcius), or has had antecedent of fever for at least 2 consecutive days at the time of screening.
- One or more of the following:
Key exclusion criteria (6 listed)
- Any condition that, in the opinion of the investigator, contraindicates participation in this study, including conditions that could hinder compliance or that could place participants or study staff at increased risk.
- Pregnancy.
- 1. Signs or symptoms of fever-associated conditions other than LF, such as urinary tract infection, or any other infection that may cause fever.
- Co-enrollment guidelines: Participants may be co-enrolled in other studies; however, study staff should be notified of co-enrollment
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Determine the prevalence and
Time frame: At time of study start
Determine the prevalence and annual incidence of seroconversion to LASV infection in the general population around each study site in the LASV-endemic area of southern Mali
Determine the incidence of LF in febrile patients attending health centers in southern Mali
Time frame: Over 3 years
Determine the incidence of LF in febrile patients attending health centers in southern Mali over 3 years.
1 secondary outcome
Determine the biological, clinical, and virologic parameters of LASV-Soromba infection in study participants with LF.
Time frame: At time of study start.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Aug 2026.
- Individual participant dataSharing planned: No. Although samples were collected prospectively all testing is performed retrospectively. Our agreement with the local health centers is to inform them of the overall results of the study and their region in particular. We do not plan to inform individuals.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Heinrich U Feldmann, M.D. principal investigator
National Institute of Allergy and Infectious Diseases (NIAID)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Lassa Virus Infection, run by National Institute of Allergy and Infectious Diseases (NIAID) at 1 site in Mali.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 13 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 28 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Mali. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Determine the prevalence and (time frame: At time of study start). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Aug 2026.