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Brown kiwi (Apteryx mantelli Bartlett), a ratite endemic to New Zealand, is currently listed as "Vulnerable" under the IUCN classification system due to predation by introduced mammals. Operation Nest Egg (ONE) raises chicks and juveniles in predator-proof enclosures until they are large enough to defend themselves. These facilities experience an environmental accumulation of coccidial oocysts, which leads to severe morbidity and mortality of these kiwi. Four species of coccidia have been morphologically described from sporulated oocysts with additional opportunistic descriptions of endogenous stages. This research continues the morphological descriptions of these species of Eimeria with an additional novel morphotype also morphologically described. It also provides the first genetic characterisation targeting the mitochondrial cytochrome c oxidase I (COI) gene. Based on these findings, it was determined there are at least five morphotypes of Eimeria that infect brown kiwi and co-infections are common at the ONE facilities surveyed. The COI amplicon targeted for this study was sufficient to provide differentiation from other members of this genus. Sanger sequencing yielded ambiguous bases, indicating the need for more in-depth sequencing., (© 2023. The Author(s).)

Coccidia (Eimeria spp.) in brown kiwi (Apteryx mantelli) cause significant morbidity and mortality in captive rearing facilities. Monitoring the abundance of this parasite in individual birds is crucial for successful management of kiwi. This research compares the abilities of centrifugal faecal flotations (CFF) and a modified Mini-FLOTAC protocol to detect oocysts. We hypothesised that the Mini-FLOTAC would detect higher oocyst counts. Kiwi dropping samples (n = 10) were homogenized in MgSO 4 (SG 1.28) and oocyst counts made with CFFs and Mini-FLOTAC counting chambers, with three replicates for each method. For CFF, 0.5 g of droppings were examined using standard methods. Mini-FLOTAC counts were made using a modified sample preparation compared with the manufacturer's protocol but still used a 1:20 dilution of droppings. Oocysts were quantified using light microscopy at ×100-300 magnification. A linear mixed-effects model by REML showed that oocyst per gram estimates via the Mini-FLOTAC method were 3.2 times higher (95% CI 2.4-4.5, p < 0.01) than the CFF results. This increased detection likely represents a more accurate estimation of parasite shedding and should be considered for use in research or applications requiring more accuracy, cost-effectiveness, or accessibility than the CFF provides.

Aim: To assess the efficacy of toltrazuril against the Eimeria spp. affecting brown kiwi (Apteryx mantelli)., Methods: Droppings were collected from three brown kiwi, aged <6 months old, at a captive rearing facility in the North Island of New Zealand, between 22 February and 20 April 2017, on 14 sampling dates. Only droppings (n=30) that were excreted between 03:00 and 07:00, as determined using video surveillance, were included for analysis, reflecting the peak time for shedding of coccidial oocysts for brown kiwi. Oocysts were quantified in each sample and Eimeria species identified on the basis of oocyst morphology. All samples were collected between 2 and 10 days after the birds had been treated with 25 mg/kg toltrazuril., Results: Eimeria spp. oocysts were identified in 28/30 individual samples and on 14/14 sampling dates. Oocyst counts varied from 0 to 328,080 oocysts per gram (opg), and at least one oocyst count >10,000 opg was measured on 12/14 sampling dates. Three species of Eimeria were observed, with Eimeria apteryxii and E. kiwii most commonly encountered, whereas only one sample contained E. paraurii., Conclusions and Clinical Relevance: In the three birds monitored at this research site, there was a high abundance of E. apteryxii and E. kiwii oocysts in droppings despite recent administration of toltrazuril. These results suggest that the populations of Eimeria spp. affecting brown kiwi at this location appear to possess an ability to survive exposure to toltrazuril. Toltrazuril is widely used at captive rearing facilities to limit the effects of coccidiosis in juvenile kiwi. If a lack of efficacy is confirmed, it will be necessary to investigate alternative treatment regimens alongside broader environmental management strategies.

Captive rearing of wild brown kiwi (Apteryx mantelli) is widely carried out to assist in the recovery of this declining species. As a consequence, high densities of immunologically naïve kiwi are commonly housed in semi-captive conditions, with the potential to result in substantial morbidity and mortality from coccidiosis caused by multiple species of Eimeria. Previous research has described circadian variation in oocyst shedding across multiple avian host species. The aim of this research was to describe any circadian variation in oocyst shedding in brown kiwi. Droppings were collected from brown kiwi (n = 4) at a single captive rearing facility using video surveillance to determine the time of excretion, and oocyst counts were undertaken. Results show that two of the Eimeria spp. affecting brown kiwi exhibit a peak in oocyst shedding between 03.00 and 07.00 with few or no oocysts shed between 08.00 and midnight. These results are not able to be explained by the current hypotheses theorising the evolutionary forces behind the development of this adaptive trait. Our findings increase the current understanding of the biology of the Eimeria spp. affecting brown kiwi and have important implications for the management of captive-reared kiwi, in particular for the accurate interpretation of faecal oocyst counts.

Circoviruses are circular, non-enveloped, single-stranded DNA viruses around 2000 nucleotides (nt) in length and include the pathogenic species, Porcine circovirus 1 and Beak and feather disease virus, capable of causing significant morbidity and mortality. This group of viruses may be robust to degradation by external environments, and avian circoviruses are known to move between closely related hosts. Using a de novo metagenomic approach, followed by confirmatory PCR, we identify for the first time a circular Rep-encoding single-stranded (CRESS) DNA virus in New Zealand kiwi, Apteryx spp., derived from faecal matter of the rowi kiwi (A. rowi) showing signs of verminous dermatitis. The entire 2085 nt genome was cloned and sequenced and contains both capsid and replicase genes, as well as a conserved 9 nt motif. Phylogenetic analyses place it within Circoviridae, adjacent to other environmental CRESS-DNA viruses, and most closely related to badger circovirus-like virus (Meles meles circovirus-like virus). As the rowi is the most critically endangered kiwi, it is vital to understand the role of rowi kiwi circovirus-like virus as a possible pathogen and also any potential cross-species transmission.

Aim: To describe a temporal cluster of avian malaria (Plasmodium spp.) at an Operation Nest Egg™ (ONE) site in Rotorua which caused mortality in a juvenile kiwi and had high population prevalence in brown kiwi (Apteryx mantelli)., Methods: A 70-day-old wild-born captive brown kiwi was submitted for post-mortem examination to Massey University Wildlife Health Centre. Post-mortem examination and histopathology were used to determine the cause of death. Plasmodium specific PCR analysis was subsequently conducted on tissue samples and 108 individual blood samples from living kiwi from five ONE breeding sites and two rowi kiwi crèches. Positive PCR products were sequenced to identify the Plasmodium spp. isolated. Where possible, blood smear microscopic examination was used to determine the level of parasitaemia in the infected kiwi., Results: Plasmodium spp. was detected in the kiwi which died and it showed histopathological evidence of disseminated protozoal infection. A high prevalence of Plasmodium was found in blood samples from kiwi concurrently residing at ONE Rotorua by blood smear microscopy (22/32, 68%) and PCR (25/32, 78%). All kiwi with positive blood smears had only a low level of peripheral parasitaemia at the time of sampling. However, 0/17 additional kiwi sampled at Rotorua 3 weeks after the juvenile's death, 0/23 Rotorua juveniles sampled 1 year later and 0/59 kiwi from the five other locations were positive for Plasmodium by these methods. Sequencing analysis revealed a cosmopolitan Plasmodium (Huffia) elongatum lineage in all positive birds., Conclusions: This is the first description of an avian malaria (Plasmodium spp.) infection associated with mortality and a high population prevalence in brown kiwi at a ONE site in the 20 years of the programme. The study suggests that this level of infection in a population of kiwi was unusual and provides evidence in support of continued vigilance of disease risks associated with this and other conservation management programmes involving wildlife translocation.