Table 2 List of minimum indicators for entomological surveillance and IRM in Nigeria

Indoor resting density (IRD)

Number of adult female vectors collected indoors per room per day (estimated from PSC collections over a 3 day period)

To determine relative abundance, indoor resting habit and suitability of local vectors for control measures such as IRS and ITNs

Human biting rate (HBR)

Number of Anopheles attempting to feed per person per unit time (estimated from CDC-LT collections)

To determine EIR

Biting cycle per location

Number of Anopheles attempting to feed per person per hour indoor/outdoor (from CDC-LT collections)

To determine peak biting times indoor and outdoor

Percentage sibling species composition

Percentage of each female Anopheles mosquito sibling species in each sentinel site (estimated from morphological and PCR identifications)

To determine species distribution and prevalence

Parity rate (PR)

Proportion of adult female vectors that laid eggs (estimated through ovary dissection)

An indicator for mosquito longevity

Sporozoite rate (SPR)

Proportion of adult female vectors harboring sporozoites in their salivary glands (determined using ELISA/PCR)

To determine EIR

Human blood index (HBI)

Proportion of blood-fed adult female vectors that fed on humans (determined with ELISA/PCR method)

To determine mosquito host preference

Entomological inoculation rate (EIR)

Number of infectious bites by adult female vectors per person per unit time (calculated as product of HBR&SPR)

To estimate the intensity of malaria transmission within the sentinel site

Resistance status

Classification of adult female vectors as confirmed resistant, possible resistant, or susceptible (WHO/CDC bioassay tests) to permethrin, deltamethrin, alphacypermethrin, bendiocarb, DDT, pirimiphos-methyl, clothianidin and chlorfenapyr

To determine response status of Anopheles populations in each site to WHO-PQ recommended insecticides

Synergist-insecticide resistance status

Involves pre-exposure to PBO before exposure to insecticide. Full restoration of susceptibility after pre-exposure to the PBO synergist suggests that the metabolic resistance mechanism (enzyme class) related to the synergist plays a role in the insecticide resistance observed

If an increase in mortality is not observed, the metabolic mechanisms related to the synergist are likely not involved in the resistance observed

To ascertain the involvement of metabolic resistance mechanism in the expression of resistance by the Anopheles mosquito population in each site

Pyrethroid Resistance intensity

Classification of vector populations as having high, moderate, or low pyrethroids (permethrin, deltamethrin, and alphacypermethrin) resistance after WHO/CDC bioassay tests at × 2, × 5 and × 10 concentrations

To determine operational significance of detected pyrethroid resistance

kdr frequency

Percentage of kdr allele occurrence in the resistant mosquito populations in each sentinel site (determined using PCR)

To determine the role and extent of target site mechanism involvement in DDT & pyrethroid resistance of An. gambiae s.l population in each sentinel sites