DIAGNOSIS is one of the most IMPORTANT steps to control outbreaks of avian malaria in captive penguins.
Penguin malaria investigations have varied success, which is most likely due to the infection stage and level of infection at the time of sampling.
Giemsa-stained thin blood smear examination is still considered the gold standard test in avian malaria diagnosis, being extremely accurate when erythrocytic parasites are detectable in red blood cells (erythroblasts or erythrocytes)
The conclusive diagnosis of avian malaria through blood smears therefore requires the observation of erythrocytic meronts, which are unique to Plasmodium spp.
Microscopic examination of blood films is an inexpensive technique that provides an estimate of the parasitaemia intensity (Waldenström et al., 2004), although for penguins this may be a poor predictor of survival, as it is common to have lethal cases in penguins with low parasitaemia (Cranfield et al., 1990). The sensitivity of this method can be low and blood smears observation may not be useful for diagnosis (Cranfield et al., 1990). It is possible to see acute infections causing mortality without parasitaemia being present. In several cases, confirmation of the disease must be achieved through histopathology or molecular methods (Cranfield et al., 1990; Dinhopl et al., 2011; Vanstreels et al., 2014, 2015). Furthermore, parasites may remain undetectable in the blood stream during chronic infections and detection by microscopy is difficult. Therefore, negative blood smears cannot be considered sufficient to rule out infection (Jarvi et al., 2002).
- Samples pre-mortem: EDTA blood, thick blood films (unfixed)
- Samples post-mortem: Fresh or frozen but not fixed material where possible of spleen, liver, lung, brain + impression smears from each. Each organ / tissue needs to be in separate labelled pots.As standard with PCRs, negative results do not exclude infection (in this case penguin malaria), however a positive result confirms the infection/diagnosis.
- The current price for this test is £235.00 excluding VAT with a turnaround time of 2-4 weeks.