New insights into diagnosis of Platynosomum fastosum (Trematoda: Dicrocoeliidae) in cats

Hepatobiliary Platynosomosis in Black-Tufted Marmosets (Callithrix penicillata): A Lethal Threat for Wildlife and Captive Populations

Helminthic infections, particularly those caused by trematodes, pose a significant health risk to both animals and humans. This study investigates hepatobiliary platynosomosis (HP) caused by Platynosomum illiciens in black-tufted marmosets (Callithrix penicillata) in Central Brazil. Data were retrospectively collected from autopsy records at the Laboratory of Veterinary Pathology and Forensics, University of Brasília, from January 2006 to July 2021. Epidemiological, clinical, and pathological information was analyzed, including comparisons between free-ranging and captive marmosets. A total of 1596 nonhuman primate (NHP) death records were examined, with black-tufted marmosets accounting for 75.6% (1206/1595) of autopsies. HP was identified in 10.8% (131/1206) of these cases. Captive marmosets showed a higher prevalence of HP (49.6%) than free-ranging ones (6.5%). This study revealed a significant seasonal trend, with higher HP prevalence observed during the wet season until the onset of the dry season. Pathological examinations revealed severe liver and bile duct damage in fatal HP cases, including fibrosis, bile duct thickening, and the presence of flukes. Captive marmosets exhibited pronounced clinical signs, such as weight loss and apathy. Morphological and molecular analysis of sampled flukes confirmed P. illiciens infecting the marmosets. These findings underscore the substantial impact of HP on marmoset populations, particularly in captive settings. The high lethality (58% overall; 81.6% in captivity) highlights the need for improved management and preventive measures in captive environments. This study contributes to understanding HP epidemiology, clinical manifestations, and pathological outcomes, underscoring the disease's significance for the health of both free-ranging and captive NHP populations. Our findings also support the need to develop targeted strategies to mitigate the impact of HP on primate species populations.

Occurrence and Risk Factors Associated with Platynosomum illiciens Infection in Cats with Elevated Liver Enzymes

Platynosomum spp., a hepatic trematode, causes fatal hepatobiliary disease in cats. Feline platynosomiasis is often underestimated due to a lack of awareness and diagnostic challenges. This study aimed to investigate the occurrence, factors, and clinicopathological abnormalities associated with Platynosomum spp. infection in cats with elevated serum ALT levels. Platynosomum infection was determined using zinc sulfate flotation and formalin-ether sedimentation. DNA sequence analysis of PCR products from the Platynosomum internal transcribed spacer 2 (ITS2) region and cox1 gene was used to identify Platynosomum species. Of a total of 43 cat fecal samples, the proportion of Platynosomum spp. infection by microscopic examination was 11.63% (5/43). All PCR-positive samples were molecularly identified as Platynosomum illiciens. From the logistic regression analysis, the odds of Platynosomum infection in cats without a deworming program were 16 times higher than those of regularly dewormed cats. Demographic data, housing conditions, and predatory behavior were not significantly associated with the infection. Regarding blood profiles, infected cats had higher eosinophil counts (p = 0.014), with no significant differences in ALT (p = 0.791) or ALP (p = 0.970) levels compared to non-infected cats. Our findings demonstrate that eosinophilia in cats with increased serum ALT may suggest P. illiciens infection in endemic areas. We strongly recommend a regular deworming program to mitigate the risk of P. illiciens infection.

Dicrocoeliidae Family: Major Species Causing Veterinary Diseases

This chapter analyses the taxonomic position of the Dicrocoeliidae family and several of its genera and species. The chapter reviews the biology of major veterinary disease-causing species, including Dicrocoelium dendriticum, Dicrocoelium hospes, Dicrocoelium chinensis, Eurytrema pancreaticum and Platynosomum fastosum. All these species have indirect life cycles with two intermediate hosts: molluscs as the first host and ants, grasshoppers and lizards as the second host. Dicrocoelium dendriticum is a widespread liver fluke found in ruminants across Europe, Asia, North Africa and North America. It can also infect humans. Dicrocoelium hospes is widely distributed in the savanna areas of Africa south of the Sahara, while D. chinensis is mainly found in ruminants in East Asia and some European countries (probably imported from Asia). Eurytrema pancreaticum is a common parasite that lives in the bile ducts, gall bladder, pancreatic ducts and intestines of ruminants. It is found in Europe, Madagascar, Asia and South America. Adults of P. fastosum live in the liver, gall bladder and pancreas of birds and mammals in Europe, Africa, Asia, North, Central and South America. Information on the epidemiology, pathology, clinical aspects, diagnosis, treatment, control, prevention and economic impact of Dicrocoeliosis caused by D. dendriticum, Eurytrematodosis and Platynosomiosis have been included.

The FLOTAC basic technique as a new extraction method for root-knot nematodes (Meloidogyne spp.) from soil and roots

FLOTAC Techniques have been widely acknowledged as an effective method for the extraction of human and animal parasites. The present study is the first application of FLOTAC basic technique (FBT) for the extraction of phytoparasitic nematodes from soil and infested plant roots. Eggs and second stage juveniles (J2) of the root-knot nematode Meloidogyne incognita were extracted from infested soil and tomato roots either by FBT and conventional nematode extraction methods, such as centrifugal flotation and root maceration techniques, respectively. The number of M. incognita J2 and eggs extracted from soil by FBT was always significantly higher compared to the extraction with the centrifugal flotation method, averaging 277 vs 35 eggs and J2 mL-1 soil. Conversely, no significant differences were observed between FBT and the root maceration technique in the extraction of eggs and J2 from tomato roots. Results demonstrated that FBT can be highly effective also for the extraction of phytoparasitic nematodes. Due to its accuracy and sensitivity, FBT seems particularly suitable for nematode surveys in wide geographical areas, where an accurate and rapid detection of present phytoparasitic nematofauna is required.

A first attempt at determining the antibody-specific pattern of Platynosomum fastosum crude antigen and identification of immunoreactive proteins for immunodiagnosis of feline platynosomiasis

Background and Aim:

Feline platynosomiasis, also known as lizard poisoning, is a feline hepatic disease caused by the parasitic trematode Platynosomum fastosum. Since this helminth resides in biliary ducts and gallbladder, the heavy infection can lead to failure of the hepatobiliary system and can be associated with cholangiocarcinoma. The primary diagnostic tool currently used is conventional fecal microscopy. However, low sensitivity of detection could occur in the case of light infection or biliary obstruction. This study aimed to determine the antibody-specific pattern of P. fastosum crude antigen and to identify immunoreactive proteins to develop the immunodiagnostic techniques.

Materials and Methods:

We investigated potential antigens specific to P. fastosum infection using western blotting. Forty-six samples of cat serum, including 16 P. fastosum-infected sera, eight healthy control sera, and 22 sera infected with other endoparasites were used. The sensitivity, specificity, positive predictive value, and negative predictive value of each band were calculated. Immunoreactive bands with high diagnostic values were further analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the protein components.

Results:

Using immunoblotting, three proteins of 72 kDa, 53 kDa, and 13 kDa were found to be immunogenic. LC-MS/MS identified these proteins as a 70 kDa heat shock protein, a hypothetical protein (CRM22_002083) (adenosine triphosphate synthase subunit beta), and histone H2B, respectively.

Conclusion:

This study is the first to reveal three proteins that could be candidates for developing diagnostic tools for feline platynosomiasis.

Acute infection with Platynosomum illiciens (Trematoda: Dicrocoeliidae) as a clinically relevant and potentially fatal disease in Falco sparverius (Aves: Falconidae) in Brazil

Platynosomum illiciens is a dicrocoeliid trematode from the biliary tract of warm-blooded vertebrates (felines, primates, marsupials, and birds) reported in different parts of the world. Although the veterinary relevance of platynosomosis in mammals, especially in domestic felines, has been increasingly evidenced in the scientific literature, studies involving avian disease caused by P. illiciens are comparatively scarce. In the present study, a female specimen of the American kestrel, Falco sparverius L., found dead, in November 2019, in Brazil, was necropsied. Parietal biliary effusion in the celomatic cavity was observed, suggesting biliary transudation and gallbladder stasis, which possibily preceded the distension and rupture of gallbladder noted during necropsy. In the microscopic analysis of the bile content, small trematodes were found and characterized as immature stages of Platynosomum after the morphological study. Partial sequences of the cox-1 gene enabled the identification of P. illiciens, with 100% similarity with previously sequenced sympatric isolates from mammals. The finding of immature specimens in a ruptured gallbladder strongly suggests a role for the parasite in biliary flow dysfunction, indicating acute platynosomosis as a clinically relevant and potentially fatal condition that has not yet been discussed.

Platynosomum fastosum in domestic cats in Cuiabá, Midwest region of Brazil

Platynosomum fastosum, which is distributed in tropical and subtropical regions, is the main parasite in the biliary system of domestic cats. Cats can be asymptomatic or show severe signs of cholangitis. Although the infection is reported throughout Brazil, only post-mortem studies are available from the Midwest region of the country. This cross-sectional study investigated the frequency of P. fastosum parasitism in domestic cats treated at the University Veterinary Hospital in Cuiabá city, Mato Grosso, Brazil, by three coproparasitological techniques (formalin-ether sedimentation, Faust, and Hoffmann), associating clinical, laboratory (haematological, biochemical) and ultrasonographic alterations. Based on the sample calculation, 171 cats were evaluated in the clinical and laboratory and a semi-structured epidemiological questionnaire was designed and used by the tutors. The prevalence observed was 26.90%, with no significant association with sex, reproductive status, age, hunting habit, access to the street, recent anthelmintic treatment, and the guardian's lack of knowledge regarding parasitism. Of the 171 cats evaluated, 55 (32.16%) showed clinical signs suggestive of cholangitis, with a significant association of this variable. Regarding the clinical and pathological variables, mild neutrophilia and elevated serum activity of alanine amino transferase and alkaline phosphatase was observed (but not significantly), while the mean values of eosinophils, leucocytes, total protein, albumin, and globulin were normal. The ultrasound findings were like those previously described. Thus, it was observed that P. fastosum occurs in moderate prevalence in cats from Cuiabá-MT, with a significant association with clinical signs and a regular agreement between the parasitological techniques employed.

Comparison of fecal analysis methods for the detection of Platynosomum fastosum in naturally infected cats

OBJECTIVES

Diagnosis of Platynosomum fastosum Kossack 1910, a liver fluke of cats, can be challenging, with infections potentially not identified depending on the fecal analysis method used. The aim of this study was to compare three methods for identification of P fastosum eggs in feces.

METHODS

Feces from 50 cats with unknown infection status from a location endemic for P fastosum were analyzed. The methods used included double centrifugation with Sheather's sugar flotation solution (specific gravity 1.28); the Mini-Parasep (Apacor) flotation kit with ZnSO4 (specific gravity 1.20); and the Mini-Parasep sedimentation kit with Triton X/ethyl acetate solution.

RESULTS

Thirty-four cats were identified as positive for P fastosum. Of these cats, 33 were identified with the double centrifugation method, 16 with the Mini-Parasep flotation kit and 11 with the Mini-Parasep sedimentation kit. Using the total number of samples identified as positive by at least one method as the true positive, the sensitivity of the methods was 97.1% for double centrifugation, 47.1% for the Mini-Parasep flotation kit and 32.4% for the Mini-Parasep sedimentation kit. Other parasite eggs (eg, Ancylostoma tubaeforme, Trichuris species and Toxocara cati) also were detected more frequently with the double centrifugation method.

CONCLUSIONS AND RELEVANCE

Of the three methods tested, double centrifugation with Sheather's sugar flotation solution was the most effective in identifying cats with P fastosum and other helminth eggs in their feces. The lower specific gravity of the flotation solution in the Mini-Parasep flotation kit likely influenced the results. A primary drawback of the Mini-Parasep sedimentation kit was the amount of sediment. While more sediment was examined than recommended in the manufacturer's instructions, this was still only a small portion of the total sediment. In addition, reading the slides took longer than with the other methods.

Infection by Platynosomum illiciens (= P. fastosum) in domestic cats of Araguaína, Tocantins, northern Brazil

Abstract Platynosomiasis is a hepatopathy caused by Platynosomum illiciens(= P. fastosum) (Trematoda: Dicrocoelidae), which occurs mainly in domestic and wild cats in tropical and subtropical areas. The objective of this study was to verify the occurrence of P. illiciens infection in domestic cats in the city of Araguaína, Tocantins, Brazil, using necropsy and coproparasitological tests. Additionally, we aimed to evaluate the use of two different techniques to diagnose P. illiciens infection in domestic cats and verify whether this parasitism was associated with individual feline characteristics. For this, 54 cats of different ages were analyzed. The percentage of infection was 33.3% (CI = 21.1-47.5%), parasite load was 9-509, mean intensity was 151.7, and mean abundance was 50.5 trematodes per animal. The risk of infection was higher for females than for males (OR = 5.00; P = 0.017). The spontaneous sedimentation coproparasitological test demonstrated the greatest sensitivity and specificity in diagnosing P. illiciens. This study is the first to report the occurrence of P. illiciens in cats in the state of Tocantins, northern Brazil.

An Additional Asset for the FLOTAC Technique: Detection of Gastrointestinal Parasites in Vegetables

INTRODUCTION

Gastrointestinal parasites are considered amongst the most important threats to veterinary and human health worldwide. The transmission of these parasitic diseases usually involves the accidental ingestion of oocysts, cysts, eggs, and larvae, whose detection is generally achieved by classical coproparasitological methods, based on sedimentation and/or flotation techniques. These procedures might be inefficient or display a low sensitivity when performed on food matrices. This study aimed to assess the value of the FLOTAC technique for the detection of different parasitic stages of gastrointestinal parasites of domestic animals in fresh lettuce.

MATERIAL AND METHODS

Samples (n = 100) were purchased from public markets located in the metropolitan region of Recife (Brazil).

RESULTS

A total of 79% scored positive for eggs and/or cysts of gastrointestinal parasites. Protozoa and nematodes were detected in 32% (32/100) and 64% (64/100) of samples, respectively, with cysts of the genus Entamoeba (32%) and eggs of nematodes of the order Strongylida (30%) being the most frequently diagnosed.

CONCLUSIONS

The findings herein reported demonstrate that the FLOTAC technique can be successfully applied for recovering food-borne parasites of medical and veterinary concern in food matrices.

Dicrocoeliidae Family: Major Species Causing Veterinary Diseases

This chapter analyses the taxonomic position of Dicrocoeliidae family and several of its genus and species. The biology of the major species causing veterinary diseases such Dicrocoelium dendriticum, Dicrocoelium hospes, Dicrocoelium chinensis, Eurytrema pancreaticum and Platynosomum fastosum, has been reviewed. All these species have an indirect life cycle, involving two intermediate hosts (molluscs as first and ants, grasshoppers and lizards as second). Dicrocoelium dendriticum is a very widespread hepatic trematode in the ruminants of many countries in Europe, Asia, North Africa and North America, even affecting humans. Dicrocoelium hospes is widely distributed in the savanna areas of Africa south of the Sahara, whilst D. chinensis has mainly been found in ruminants in East Asia and some European countries (probably imported from Asia). Eurytrema pancreaticum is a common parasite whose adults live in ruminant bile ducts, gall bladder, pancreatic ducts and intestines in Europe, Madagascar, Asia and South America. Adult P. fastosum live in the liver, gall bladder and pancreas of birds and mammals in Europe, Africa, Asia, North, Central and South America. Information about the epidemiology, pathology, clinical aspect, diagnosis, treatment, control, prevention and economic impact mainly of Dicrocoeliosis produced by D. dendriticum, as well as of Eurytrematodosis and Platynosomiosis, has been included.