Outbreak of Philophthalmus gralli in four greater rheas (Rhea americana)

Abstract

Using slit‐lamp biomicroscopy, conjunctival biopsy, and morphological identification, a flock of four Greater rheas (Rhea americana) in Arizona were diagnosed with conjunctivitis secondary to Philophthalmus gralli (P. gralli) infection. Aquatic snails from the exhibit’s water source were identified as Melanoides tuberculatus, a known vector for P. gralli. Comparison of partial sequences of DNA regions from P. gralli adults removed from the rheas and metacercariae from the aquatic snails demonstrated a 100% match, confirming the source of infection. The flock was divided into two treatment groups: the most severely affected rheas received both manual removal of trematodes and praziquantel 1% ointment OU q12 h and the least severely affected rheas were only given praziquantel 1% ointment OU q12 h. The rheas were permanently relocated away from the infected water source and aquatic snails. Initial resolution was seen at 17 weeks in the most severely affected rhea, which had 675 adult P. gralli removed and topical praziquantel. The two rheas that only received topical praziquantel showed resolution within 3 and 15 weeks. Current recommendations for treating P. gralli include: manual removal of trematodes, topical praziquantel 1% ointment, and relocation away from infected water sources and aquatic snails.

Preclinical Evaluations of Modified Rice Hydrogel for Topical Ophthalmic Drug Delivery of Praziquantel on Avian Philophalmiasis

“…The morphological characteristic of P. gralli was confirmed under an optical microscope. Moreover, the conjunctival trematode from the ostrich in the present study was identified as P. gralli , which was submitted to GenBank database under accession numbers MZ088139, 99.92% identity to P. gralli isolate from Greater rheas (Rhea Americana) in Arizona (JQ246434) [ 20 ].…”

“…Furthermore, the phenotypic and the genotypic characteristics of P. gralli were confirmed by using the optical microscope and the direct sequencing of PCR product, respectively. The parasite sequences were found in GenBank, with accession numbers from Greater rheas ( Rhea Americana ) in Arizona [ 20 ]. These processes ensured the accuracy of P. gralli identity that was used in this study.…”

“…Genomic DNA (gDNA) was extracted using the NucleoSpin DNA RapidLyse Kit (Macherey-Nagel GmbH, Düren, Germany) according to the manufacturer’s instructions. The partial sequence of large 28S ribosomal RNA gene, approximately 1300 base pairs, was analyzed using forward primer digl2 (5′-AAGCATATCACTAAGCGG-3′) and reverse primer 1500R (5′-GCTATCCTGAGGGAAACTTCG-3′) with four internal primers including 300F (5′-CAAGTACCGTGAGGGAAAGTTG-3′) and 900F (5′-CCGTCTTGAAACACGGACCAAG-3′); internal reverse primers: 300R (5′-CAACTTTCCCTCACGGTACTTG-3′) and ECD2 (5′-CTTGGTCCGTGTTTCAAGACGGG-3′) PCR was performed following protocol described previously [ 20 ]. The cycle-sequenced using ABI BIGDYE™ (Foster City, CA, USA) chemistry, alcohol-precipitated, and run on an ABI PRISM 3100™ automated capillary sequencer.…”

Potential for emergence of foodborne and waterborne trematodiases in California

“…Although native to Asia and Africa, the snail has been introduced around the world, including in the Americas from the United States to southern Brazil (Murray 1971, Facon et al 2003, Coelho et al 2018, CABI 2020, Chalkowski et al 2021). At least three human-pathogenic, zoonotic trematodes have been co-introduced with the snail in the Americas (see Scholz et al 2001, Pinto & Melo 2011 and refs therein), including reports in the continental United States of all three species in Texas (Nollen & Murray 1978, Mitchell et al 2000, Tolley-Jordan & Owen 2008), one in Arizona (Church et al 2013), and another in Utah and Florida (Mitchell et al 2005). However, M. tuberculata is much more widespread throughout the Unites States (Chalkowski et al 2021) than the few places the trematodes have been reported.…”

Mycobacterieel conjunctivaal granuloom bij een Chinese zaagbekeend (Mergus squamatus)

“…en Cryptosporidium spp. en myiasis (Abrams et al, 2002;Dubey, 2002;Elias et al, 2008;Lopez et al, 2010;Church et al, 2013;Dunham et al, 2016). Veel van deze parasieten komen echter zelden voor in West-Europa en infecties worden vaak uitsluitend waargenomen bij in het wild levende dieren of in het wild gevangen dieren.…”