Avian malaria in introduced, native and endemic New Zealand bird species in a mixed ecosystem

Abstract

Avian malaria, caused by Plasmodium spp., has been reported as a cause of morbidity and mortality in New Zealand bird populations. The prevalence of Plasmodium lineages in the Waimarino Forest was evaluated in NZ robins (Petroica longipes), other passerines, blue ducks (Hymenolaimus malacorhynchos), and brown kiwi (Apteryx mantelli), using nested PCR. The presence of P. sp. lineage LINN1, P. (Huffia) elongatum lineage GRW06 and P. (Novyella) sp. lineage SYAT05 was demonstrated; Plasmodium (Haemamoeba) relictum lineage GRW4 was not found. The highest prevalence of infection was found in introduced European species (80.5%), followed by native (19%) and endemic species (3.5%), with a significant difference between these groups. All detected Plasmodium lineages have previously been identified in New Zealand and introduced species have been suggested as an important reservoir of infection. The results of this study will aid New Zealand conservation managers with disease risk management during bird translocations from the Waimarino forest.

Is Avian Malaria Playing a Role in Native Bird Declines in New Zealand? Testing Hypotheses along an Elevational Gradient

“…These findings are similar to those from previous surveys conducted in New Zealand [17,19–21]. Although our second hypothesis did not hold up in a statistically significant manner (there was only a trend of malaria prevalence decreasing with increasing elevation), our findings with regards to prevalence in native versus non-native birds, combined with there being more non-native birds at lower elevations at our field site (Fig 1) and elsewhere in NLNP [24], mean that there were more infected birds (from which malaria could be transmitted) at lower elevations.…”

“…Given the generally low avian malaria prevalence reported in native birds in New Zealand (with only two or three exceptions; [20,21]), it is indeed most likely that non-native species act as the primary reservoirs for avian malaria in New Zealand [19]. Based on data from the current study, we suggest that the Turdus spp.…”

“…individuals move frequently between habitat types during the breeding season [49] and can penetrate deep into New Zealand forests, while most other non-native bird species do not [50]. Similar patterns of malaria infection have been found in other areas of New Zealand, with Turdus species often having the highest prevalence and being caught in more habitat types than other non-native species [17,19–21]. Identifying potential key reservoir hosts in a disease system helps to better understand the factors driving transmission.…”

“…Lineage GRW06 is considered to have the widest host range in New Zealand [22]. Lineage LINN1 has only been reported in native species in extremely low numbers [17,20,21,45], two instances of which involved deaths of great spotted kiwi due to malaria infection [17,46]. This could have implications at NLNP where currently exists a population of approximately 25 great spotted kiwi, with documented cases of successful breeding [47].…”

“…Plasmodium parasites have also been confirmed in multiple non-native species in New Zealand [17–21], with the suggestion that some may be acting as reservoirs for spillover infection to native species [19]. The exact number of Plasmodium lineages (defined by unique sequences of parasite mitochondrial cytochrome b DNA) in New Zealand is unclear, but as many as 17 have been reported, with four generally accepted non-native lineage clusters [17,20,22].…”