Few studies have focused on malaria co-infections, mainly caused by Plasmodium falciparum, occurring mainly in children under 5 years of age in sub-Saharan Africa. These studies have focused on malaria-associated bacterial sepsis, with an estimated prevalence of 9.1% and associated mortality of 15.0%. However, no study has documented infectious sites other than the blood compartment, considered viruses and parasites as possible causes of infection in addition to bacteria, and used molecular diagnostic methods based on PCRs, which are more sensitive. Thus, the prevalence of these co-infections and the spectrum of pathogens involved are probably underestimated, as is the impact of these co-infections on mortality. Furthermore, it has been shown that malaria infections can condition the immune cells of naturally exposed individuals, potentially leading to greater susceptibility to all types of infection. But these mechanisms have never been documented in the context of co-infections.

The WHO recommends the use of broad-spectrum antibiotics in cases of severe malaria, in addition to antimalarial drugs, as it can be difficult to differentiate clinically between severe malaria and severe bacterial infection (bacteremia, pneumonia and meningitis). Yet this empirical use of antibiotics could be contributing to an increase in antibiotic resistance. Identifying the determinants of co-infection with malaria and severe bacterial infection would enable this treatment to be better targeted.

These determinants remain undetermined as no study has considered other causes of severe bacterial infection other than bacteremia, used appropriate statistical methodology (univariate analysis only) and explored important determinants, notably the capacity of children's innate immunity to respond to severe bacterial infection.

This is a prospective multicenter longitudinal study.

The study will focus on several populations:

• febrile children: aged between 6 and 60 months consulting ;
• non-febrile children: aged between 6 and 60 months consulting.
• Pregnant women.
• newborns: those born to mothers included in the study with or without pregnancy-associated malaria.

The study will be based on :

• Clinical and microbiological documentation of acute febrile episodes in recruited children
• Documentation of vital status in children 3 months after recruitment
• Ability of host cells to respond to infections.

Inclusion Criteria:

Febrile children:

• aged between 6 and 60 months
• with a febrile episode lasting less than 7 days (axillary temperature >=37.5° Celsius)
• whose state of health is compatible with a minimum single blood sample volume of 6.25 ml

Non-febrile children:

• aged between 6 and 60 months
• with axillary temperature <37.5° Celsius
• no clinical signs of infection at the time of inclusion
• no infectious episode or fever for 7 days

Pregnant women :

• giving birth in the project's partner health center
• intending to reside in the study area during the newborn follow-up period
• with a mono-fetal pregnancy
• With an apparently uncomplicated delivery not requiring referral to a higher-level health facility

Newborns at delivery:

• Born at term (determined by Ballard score)
• whose parents or legal guardians reside in the study area during the newborn's follow-up period

Exclusion Criteria:

For all :

- person already participating in another biomedical research project.

For febrile and non-febrile children:

- chronic non-infectious pathology (cancer, malnutrition, etc.)

For pregnant women

• scheduled caesarean section for current pregnancy
• Caesarean section in previous pregnancies
• chronic non-infectious pathology during pregnancy (diabetes, hypertension, pre-eclampsia)