BACKGROUND Influenza infection does not always cause clinical illnesses, so serological surveillance has been used to determine the true burden of influenza outbreaks. This study investigates the accuracy of measuring cumulative incidence of influenza infection using different serological survey designs. METHODS We used a simple transmission model to simulate a typical influenza epidemic and ...

In order to assess the reliability of the thick smear in a Plasmodium infection area, 322 thick smears were examined by a trained microscopist in field conditions. Later, the same smears were examined by an experience microscopist in ideal laboratory conditions. Reliability was measured by the Kappa index. In symptomatic malaria patients the Kappa index was 0.91 (IC 95% 0.57-0.98 p<0.05) while ...

The objective of this study was to investigate risk factors for norovirus-associated infectious intestinal disease (IID) and asymptomatic norovirus infection. Individuals with IID and healthy controls were recruited in a community-based study in England (1993-1996). This is the first risk-factor study to use viral load measurements, generated by real-time RT-PCR, to identify cases of norovirus-...

Long known as a pathogen of poultry, Mycoplasma gallisepticum (MG) was first detected in house finches in 1994. The disease rapidly spread throughout the eastern United States and Canada and was associated with debilitating disease and high mortality in house finches. However, in the late 1990s, the proportion of infected finches dying as a result of infection with MG decreased, and asymptomati...

Asymptomatic bacteriuria in elderly individuals has been well described in institutionalized settings, but to a lesser extent in the community. The purpose of this study was to determine the pathogens responsible for asymptomatic bacteriuria in elderly and middle-aged individuals in Alajue-Ede, South-Western Nigeria, and to identify any associated factors. Mid-stream urine samples were collecte...

BACKGROUND An important issue associated with the control of visceral leishmaniasis is the need to identify and understand the relevance of asymptomatic infection caused by Leishmania infantum. The aim of this study was to follow the course of asymptomatic L. infantum infection in children in an area of Brazil where it is endemic. The children were assessed twice during a 12-month period. MET...

Evolutionary theory hypothesizes that intermediate virulence maximizes pathogen fitness as a result of a trade-off between virulence and transmission, but empirical evidence remains scarce. We bridge this gap using data from a large and long-standing HIV-1 prospective cohort, in Uganda. We use an epidemiological-evolutionary model parameterised with this data to derive evolutionary predictions ...

OBJECTIVE To compare a PCR assay and direct agglutination test (DAT) for the detection of potential markers of Leishmania infection in 231 healthy subjects living in a kala-azar endemic focus of Nepal. METHODS The sample was composed of 184 (80%) persons without any known history of KA and not living in the same house as known kala-azar cases (HNK), 24 (10%) Healthy Household Contacts (HHC) a...

Visceral leishmaniasis (VL) is a serious parasitic disease, causing high morbidity and mortality in the developing world. The pathogenesis of VL is complex, and the clinical presentation ranges from asymptomatic infection to severe and fatal disease. Despite a wealth of research on the full-blown "clinical VL" syndrome, asymptomatic leishmania infections remain poorly understood. Asymptomatic i...

Staphylococcus aureus produces a particular morphological variant called small colony variant (SCV) which is responsible for persistent subclinical infections in predisposed individuals and is usually resistant to aminoglycosides and cell wall active antibiotics. Infections by SCV of S. aureus are an upcoming problem due to difficulty in laboratory diagnosis and resistance to antimicrobial chem...