Penguins are competent hosts of Haemoproteus parasites: the first detection of gametocytes, with molecular characterization of Haemoproteus larae

Abstract

Background: The majority of penguins (Sphenisciformes) have evolved in areas with weak or absent transmission of haemosporidian parasites and are usually naïve to avian haemosporidian infections. Plasmodium parasites are transmitted by mosquitoes, and lethal avian malaria has been often reported in captive penguins in many countries. The related haemosporidian parasites belonging to Haemoproteus and Leucocytozoon have also been detected in penguins but less often than Plasmodium infections. The majority of Haemoproteus infection reports in penguins are based solely on PCR-based diagnostics. It remains unclear if haemoproteids can complete their life-cycle and produce infective stages (gametocytes) in penguins or whether these infections are abortive in penguins, and thus dead ends for transmission. In other words, it remains unknown if penguins are competent hosts for Haemoproteus parasites, which cause disease in non-adapted birds. Methods: Two captive African penguins (Spheniscus demersus) and two Magellanic penguins (S. magellanicus) were found to be positive for Haemoproteus infection in two open-air aquariums in Japan, and the parasites were investigated using both PCR-based testing and microscopical examination of blood films. Samples from a black-tailed gull (Larus crassirostris) and previously tested gulls were used for comparison. Results: The lineage hSPMAG12 was detected, and gametocytes of Haemoproteus sp. were seen in the examined penguins and gull. Observed gametocytes were indistinguishable from those of Haemoproteus larae, which naturally parasitize birds of the genus Larus (Laridae). The detected sequence information and Bayesian phylogenetic analysis supported this conclusion. Additionally, morphologically similar gametocytes and closely related DNA sequences were also found in other gull species in Japan. Phylogenetic analysis based on partial cytb sequences placed the lineage hSPMAG12 of H. larae within the clade of avian haemoproteids which belong to the subgenus Parahaemoproteus, indicating that Culicoides biting midges likely transmit the parasites between penguins and gulls. Conclusions: This study shows that some species of Haemoproteus parasites complete their development and produce gametocytes in penguins, which may be source of infection for biting midges transmitting haemoproteosis. To prevent haemosporidiosis in zoos, we call for control not only of mosquitoes, but also biting midges.

First records of prevalence and diversity of avian haemosporidia in snipe species (genus Gallinago) of Japan

“…By pairwise distance, the closest morphological species to the detected Haemoproteus lineages was H. larae . This species has been detected by microscopy in various charadriiform birds ( Peirce, 1981 ; Valkiūnas, 2005 ; Yakunin, 1972 ) and was recently genetically described from rescued charadriiform birds ( Inumaru et al, 2017 , 2020 ). In this study, blood slides were not obtained, and morphological identifications could not be made.…”

Vector incrimination and transmission of avian malaria at an aquarium in Japan: mismatch in parasite composition between mosquitoes and penguins

“…While PCR is a highly sensitive tool for detection of DNA, extremely low parasitaemia may possibly be below the detection limit. In a recent study, PCRs of Haemoproteus -infected penguin DNA were negative using 50 ng DNA template, but positive using 200 ng DNA [ 22 ]. All PCR tests in this study were done using 50 ng of DNA template.…”

“…pipiens group were far less investigated due to the limited sample size, and such species may possibly be involved in the transmission of this lineage. The latter was recently identified as Haemoproteus larae and is suggested to be transmitted between captive penguins and wild gulls via biting midges [ 22 ]. The aquarium in this study is located on the coast where gulls are frequently seen.…”

“…OTULEM04 from a Sunda scops-owl ( Otus lempiji ) rescued in central Japan. Amplifications were confirmed and positive samples were sequenced following a previously described protocol [ 22 ]. The obtained sequences were assembled and compared with sequences in the GenBank database using the Basic Local Alignment Search Tool (BLAST) [ 23 ] and the MalAvi database [ 24 ].…”

Untangling the actual infection status: detection of avian haemosporidian parasites of three Malagasy bird species using microscopy, multiplex PCR, and nested PCR methods

“…A newly established multiplex PCR assay (Ciloglu et al 2019), based on the simultaneous amplification of gene fragments of the three haemosporidian genera, allows improved detection of mixed infections in birds. Although the multiplex PCR method has been used frequently in recent years (Dimitrov et al 2019;Inumaru et al 2020;Ellis et al 2020;Schumm et al 2021;Meister et al 2021), only one paper has addressed the issue of mixed infections in more detail (Neto et al 2020).…”