Table 1 Studies reporting malaria and NTS bacteraemia in children

Burkina Faso (rural) [68]

711

<15 y

All admitted children with measured fever or clinical signs of severe illness

BC

M, RDT

RDT positivity rate was higher in those with NTS bacteraemia (81%) compared to those with other bacterial infections (31%) (p <0.001)

Tanzania (rural + urban) [16]

3,639 + 457

2 m-13 y

Admitted children with measured fever or history of fever

BC

M, RDT

Children with recent malaria had higher rates of NTS bacteraemia compared to those without recent malaria (adjusted OR =4.13(95% CI = 2.66-6.44)

DRC (mainly rural) [69]

3,311

<=14 y and adults

Signs suggestive of bacteraemia or focal signs

BC

M and/or RDT

Majority of children (82%) with Salmonella had falciparum malaria infection, NTS not seasonal, comparison group not mentioned

Kenya (rural + urban) [5]

5,716

-

Children with fever, severe respiratory illness, admitted patients

BC

M

Evidence of correlation between positive malaria cases and NTS bacteraemia, no clear seasonal pattern, no comparison group

Kenya (rural) [14]

292

3 m-13 y

Cases: admitted children whose BC grew pathogenic bacteria

BC

M or RDT

Those with haemozoin in blood leucocytes were more likely to have NTS bacteraemia compared to those without haemozoin OR 16.5 (95% CI = 3.44-79.3)

Controls: healthy children individually matched to cases on age, sex and residential location

Tanzania (rural) [18]

6,836

2 m-14 y

History of fever, clinical signs of severe malaria, fever surveillance

BC

M and RDT

Evidence of reduction in NTS bacteraemia associated with severe malaria reduction

Kenya (rural) [58]

585

1-36 m

Children with malaria aged 1–36 m

BC

M

NTS was the most common isolate in children with malaria, comparison group not mentioned

DRC (rural) [20]

1,528

-

Febrile children admitted, hypothermia, other clinical signs

BC

M

40% of NTS bacteraemia had malaria co-infection compared to 1% for typhoid bacteraemia, no seasonality of NTS

Tanzania (rural) [6]

1,502

2 m-14 y

Fever + signs of severity

BC

M or RDT

73% with NTS infection had malaria compared to 21% for those with typhoid fever (p < 0.01) and compared to 40% for other bacteraemia (p < 0.01) - association more for recent than current malaria

Ghana (rural) [64]

948, 1,032 cultures

2 m-5 y

Children 2 m-5 y admitted

BC

-

24% of children with NTS bacteraemia had malaria infection compared to 18% for other bacteraemia (S. pneumoniae), no significance test mentioned

Tanzania (rural) [4]

3,639

2 m-12 y

Fever, non-infectious cause of fever excluded

BC

M, RDT

52% NTS in slide positive compared to 45% in slide negative, no significance test mentioned

The Gambia (rural + urban) [19]

-

-

-

BC

-

NTS reduction associated with malaria reduction

Kenya (rural) [22]

3,068^a

-

Children with clinical suspicion of severe malaria and culture results available

BC

M

NTS more in parasitaemic children compared to non-parasitaemic children (p = 0.05)

Mozambique (rural) [104]

1,780

<5 y

Children <5 y with severe malaria

BC

M

NTS among frequent bacteria in patients with severe malaria but no evidence of association

Mozambique (rural) [26]

23,686

<15 y

Children <15 y admitted

BC

M

About 44% of bacteraemic patients had malaria co-infection. No 7comparison with control and no mention of NTS specifically

Nigeria (urban) [118]

235

0-45 m

Children with fever with or without other symptoms

BC

M

Co-infection with S. enteritidis and malaria present, no mention of control group

The Gambia (urban) [41]

871

2 m-80 y

Clinically ill patients

BC

M

NTS 20% in slide positive compared to 57% in slide negative but not statistically significant, few cases of NTS

Tanzania (urban) [65]

1,787

0-7 y

Clinical suspicion of systemic infection

BC

M

No evidence of association between malaria and NTS

Malawi (urban) [24]

1,388

≥6 m

Children with severe malaria and BC results

BC

M

NTS bacteraemia higher in those with severe malaria anaemia (7.6%) compared to other severe malaria entities [CM + SMA] (4.7%) compared to CM (3.0%) p <0.0001]

Kenya (urban) [66]

332

4 w-84 m

NTS bacteraemia or gastroenteritis

BC

M

More than half of malaria confirmed children had NTS, no seasonal pattern. Proportion in control group not mentioned

The Gambia (rural) [27]

330

2-29 m

Ill children admitted

BC

M or RDT

No difference in proportion of malaria infection between those with NTS infections compared to other infections

Kenya (rural) [15]

166

<13 y

Children with Salmonella bacteraemia

BC

M or RDT

More NTS in rainy season; recent malaria (RDT positive) but not current malaria was a risk factor for NTS bacteraemia compared to non-bacteraemic patients (OR = 1.8, 95% CI 1.0-3.1)

Kenya (rural) [43]

2,830

>3 y

Children admitted for malaria (parasite positive) and for other illnesses (parasite negative)

BC

M

Salmonella spp. bacteraemia more common in those parasite positive. No specific mention of NTS bacteraemia

DRC (rural) [23]

779

1 m-15 y 8 m

Children with and without fever

-

M

A positive blood smear associated with bacteraemia (including NTS). There was enough evidence that 25% of malaria positive had bacteraemia compared to 14% for malaria negative

Malawi (urban) [13]

2,123

<1-15 y

Children with clinical suspicion bacteraemia (febrile) and low level parasitaemia or after anti-malarial

BC

M

Children with NTS bacteraemia more likely to have parasitaemia compared to other bacteraemia (RR 2.4, 95% CI 1.46-3.96), NTS increase in rainy season

Malawi (urban) [21]

299

0-14 y

Sick children with NTS bacteraemia, focal sepsis excluded

BC

M

NTS increase in rainy season, coincides with malaria, NTS associated with severe anaemia, malaria parasitaemia compared to other causes of bacteraemia

Kenya (rural) [63]

783

-

Children with severe malaria

BC

M

6 out of 540 children with severe malaria (and BC results available) had NTS, bacteraemia common in children with severe malaria

DRC (rural) [29]

120

1-15 y

Clinically ill in wards and outpatient

BC

M

Concurrent malaria parasitaemia and bacteraemia in 25% of cases

The Gambia (rural) [70]

2,898

<5 y

Clinical signs of pneumonia, meningitis, septicaemia

BC

M

Salmonella bacteraemia increased during rainy season, those with malaria pigment more likely to be found in those with Salmonella infections compared to other infections (RR = 4.05, 95% 1.15-14.42), comparison not done specifically for NTS

Nigeria (rural + urban) [67]

56

<5 y

Case series with positive BC, referred

BC

M

Increase in cases of paratyphoid fever during rainy season

The Gambia (urban) [17]

247

Clinically ill children with positive blood culture

BC

M

Patients with NTS bacteraemia had higher prevalence of malaria parasitaemia compared to other bacteraemic patients (X² = 9, p < 0.01)