Tracking platyhelminth parasite diversity from freshwater turtles in French Guiana: First report of Neopolystoma Price, 1939 (Monogenea: Polystomatidae) with the description of three new species

Abstract

BackgroundPolystomatid flatworms in chelonians are divided into three genera, i.e. Polystomoides Ward, 1917, Polystomoidella Price, 1939 and Neopolystoma Price, 1939, according to the number of haptoral hooks. Among the about 55 polystome species that are known to date from the 327 modern living chelonians, only four species of Polystomoides are currently recognised within the 45 South American freshwater turtles.MethodsDuring 2012, several sites in the vicinity of the cities Cayenne and Kaw in French Guiana were investigated for freshwater turtles. Turtles were collected at six sites and the presence of polystomatid flatworms was assessed from the presence of polystome eggs released by infected specimens.ResultsAmong the three turtle species that were collected, no polystomes were found in the gibba turtle Mesoclemmys gibba (Schweigger, 1812). The spot-legged turtle Rhinoclemmys punctularia (Daudin, 1801) was infected with two species of Neopolystoma Price, 1939, one in the conjunctival sacs and the other in the urinary bladder, while the scorpion mud turtle Kinosternon scorpioides (Linnaeus, 1766) was found to be infected with a single Neopolystoma species in the conjunctival sacs. These parasites could be distinguished from known species of Neopolystoma by a combination of morphological characteristics including body size, number and length of genital spines, shape and size of the testis. They were also differentiated at the molecular level using the cox1 gene marker. Based on morphological and genetic evidences, three new species are described herein, namely Neopolystoma cayensis n. sp. and Neopolystoma guianensis n. sp. from the bladder and the conjunctival sacs of R. punctularia, respectively, and Neopolystoma scorpioides n. sp. from the conjunctival sacs of K. scorpioides. However the monophyly of Polystomoides and Neopolystoma is still questioned regarding their phylogeny based on a dataset comprising four concatenated genes, namely, 18S, 28S and 12S rRNA genes and cox1.ConclusionsIn addition to these being the first chelonian polystomes to be reported and described from French Guiana, they represent the first polystomes from the hosts K. scorpioides and R. punctularia and the first representatives of Neopolystoma from South America. Chelonian polystomes now require an in-depth morphological study to reconcile the taxonomy of the genera with species evolution.

Comparative preventive efficacy of ProHeart® 12, Heartgard® Plus and Interceptor® Plus against a macrocyclic lactone-resistant strain (JYD-34) of heartworm (Dirofilaria immitis) in dogs

“…The studies reported here are the first studies demonstrating the efficacy of ProHeart 12 in preventing the development of any ML-resistant heartworm strains in dogs. ProHeart 6, an extended-release injectable suspension using the exact same formulation as ProHeart 12 but at one-third the dose (0.17 mg/kg) of ProHeart 12, was 99.5% effective against the same JYD-34 strain, when treatment was administered 2 days before inoculation with L3 [ 15 ]. Additionally, ProHeart 12 was 100% effective in a large multi-site field study involving ~ 300 dogs from 19 clinics [ 14 ] across the United States, with 142 cases from the southern US region and 42 of the cases from the Lower Mississippi River Valley (LMRV) where strains of heartworm resistant to MLs have been identified [ 20 ].…”

“…ProHeart ® 6, the same microsphere formulation as ProHeart 12 but administered at one-third the dose (0.17 mg/kg) of ProHeart 12, was 100% effective in preventing the development of a susceptible heartworm strain for 6 months; however, against a ML-resistant strain, ProHeart 6 was ineffective at the end of 6 months [ 10 ]. In contrast, when dogs were dosed at the same time as heartworm inoculation (mimicking infection at the time of initial dosing or at the end of the initial dosing interval followed by re-dosing) ProHeart 6 was 99.5% effective against a ML-resistant strain [ 15 ]. Additionally, in a large field study including ~ 300 client-owned dogs presented as veterinary patients, ProHeart ® 12 was 100% effective in preventing heartworm disease in the United States, including in dogs from areas where ML-resistant heartworm strains have previously been isolated [ 20 ].…”

Neotropical Turtle Blood Flukes: Two New Genera and Species from the Amazon River Basin with a Key to Genera and Comments on a Marine-Derived Parasite Lineage in South America

“…The South American pleurodires remain especially undersampled for parasites. Recent parasitological surveys focused on ectoparasites and gastro-intestinal helminths have highlighted this gap in knowledge and have begun addressing it (e.g., Mascarenhas et al, 2013Mascarenhas et al, , 2016Fernandes and Kohn, 2014;Viana et al, 2016;Du Preez et al, 2017;Correa et al, 2018;Pereira et al, 2018). In contrast, and perhaps owing to the difficulty in extracting taxonomically useful specimens from turtle blood, the blood parasites of freshwater turtles in South America remain unsampled.…”

Field study to investigate the effectiveness and safety of a novel orally administered combination drug product containing milbemycin oxime and lotilaner (Credelio® Plus) for the prevention of heartworm disease (Dirofilaria immitis) in client-owned dogs in the USA

“…MO used alone or in combination with other oral parasiticides has been used safely for a number of years for intestinal nematode control and HW prevention in dogs [ 27 ]. Lotilaner as a standalone product administered for fleas and ticks has demonstrated safety for dogs under field use and laboratory conditions [ 28 – 31 ].…”