Search

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 MgSO4 (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

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.

This study used morphological techniques to describe and name four new species of coccidia from the brown kiwi (Apteryx mantelli). Four distinct eimerian oocyst species were recovered that we describe as new species. The largest of these, Eimeria paraurii n. sp. measured 32.2 × 19.8 μm and is morphologically similar to gametocytes previously described histologically in colorectal polyps (Morgan et al. in Parasitol Res 111(4):1689-1699, 2012). Eimeria apteryxii n. sp. measured 23.9 × 14.9 μm and is similar to renal oocysts described histologically in brown, rowi (A. rowii) and Haast tokoeka kiwi (A. australis "Haast") (Morgan et al. in Avian Pathol 42(2):137-146, 2013). Eimeria kiwii n. sp. measured 14.8 × 13.9 μm and resembled gametocytes described previously in kiwi intestinal epithelial cells in brown kiwi (Morgan et al. in Parasitol Res 111(4):1689-1699, 2012). Eimeria mantellii n. sp. measured 17.8 × 10.7 μm and did not appear similar to any coccidia previously described in histological studies in kiwi. These are the first species of Eimeria to be described and named from brown kiwi. Because the morphological descriptions in the present study were determined from a limited number of kiwi droppings from two geographical locations, it is likely that these represent only a portion of Eimeria species present in other populations of both brown kiwi and other Apteryx species from around New Zealand.

Enteric coccidiosis may cause significant morbidity and mortality in juvenile brown kiwi (Apteryx mantelli). Morphology of sporulated oocysts indicates that at least two Eimeria species are able to infect the brown kiwi. A histological study of the endogenous stages of coccidia was undertaken in the intestinal tracts of ten naturally infected young kiwi. Sequential sectioning of the entire intestinal tract allowed identification and recording of the distribution of the various coccidial life stages. Macromeronts measuring 268 × 162 μm when mature were found mainly within the lamina propria of the proximal one third of the small intestine. A smaller form of lamina propria meront was also identified (8.7 × 6.4 μm) with a similar distribution to the macromeronts. Small meronts (4.4 × 3.8 μm) were also identified in mucosal epithelial cells, with the overall peak in distribution within the intestinal tract being distal to the lamina propria meronts. Three morphologically distinctive gametocytes were identified. Type A gametocytes contained within epithelial cells shared the same distribution as the epithelial meronts. Polyps containing large numbers of type B gametocytes within the distal intestinal tract were found in two cases, and type C gametocytes were identified throughout the entire intestinal tract in one case only. The observational nature of this study precludes complete knowledge of the parasite life cycles using histology alone. However, it is likely that each of the three morphologically distinct gametocytes represents a separate species of enteric coccidia.