The passive surveillance systems that are currently the backbone of malaria surveillance globally are in many settings inadequate for the task of identifying and targeting high-risk populations for several reasons.First, individuals with the greatest exposure may be more likely to develop partial immunity resulting in asymptomatic or sub-clinical infection and, therefore, may be disproportionately less likely to present for care .Malaria control programmes typically rely on passive surveillance and national household surveys to monitor malaria burden and intervention coverage in the general population, with additional emphasis on young children and pregnant women due to their higher risk of severe disease.The establishment of a robust passive surveillance system remains fundamental for any malaria programme aiming for elimination, including a transition to case-based reporting and case investigation.Four cloned unique sequences from the human Y chromosome, two of which are found only on the Y chromosome and two of which are on both the X and Y chromosomes, were hybridized to restriction enzyme-treated DNA samples of a male and a female chimpanzee ().One of the human Y-specific probes hybridized only to male DNA among the humans and great apes, and thus its Y linkage and sequence similarities are conserved.To eliminate malaria, malaria programmes need to develop new strategies for surveillance and response appropriate for the changing epidemiology that accompanies transmission decline, in which transmission is increasingly driven by population subgroups whose behaviours place them at increased exposure.
As malaria programmes move from control to elimination, they need to reorient their surveillance and response systems to the changing epidemiology that accompanies transmission decline.
HIV transmission in most countries is focal or “concentrated” in high-risk populations, which face barriers to testing due to the illegality and stigma of the behaviours linked to increased risk and are not efficiently or effectively identified through household surveys .
In HIV, these circumstances have led to distributions of reported cases that often do not reflect the relative contribution of different subpopulations to transmission or the current epidemiological situation .
These high-risk populations are thought to contribute disproportionately to sustaining transmission in low transmission areas and present challenges for reintroduction following elimination.
They include groups that primarily acquire and transmit infection locally .
Third, even when high-risk individuals seek treatment, most passive surveillance systems do not gather the data that would be necessary to identify behavioural risk factors and effectively target behavioural risk groups.