Disseminated toxoplasmosis in Antillean manatees Trichechus manatus manatus from Puerto Rico

Analysis of a long-term dataset of Antillean manatee strandings in Belize: implications for conservation

We analysed 23 years of data on strandings of the Antillean manatee Trichechus manatus manatus in Belize, documented by the Belize Marine Mammal Stranding Network, to examine the threats to this population. A total of 451 stranding incidents were reported, of which 376 (83.4%) cases were verified. A total of 286 (63.4%) of the incidents occurred within Belize District, where the number of strandings has almost tripled since 2009. Watercraft collisions accounted for the highest number of strandings, with 131 confirmed cases, and is the leading cause of anthropogenic mortality for this population. Collision with watercraft is an emerging and major threat to manatees in Belize, and is correlated with increases in human activity, in particular associated with tourism. This finding of high levels of manatee deaths in Belize is consistent with trends previously reported for manatees in Florida and Puerto Rico. This work can provide guidance to detect and address similar patterns of mortality in other Antillean manatee populations across the species' range. There is a need for greater awareness of the threats facing the species and its habitat, for stakeholder partnerships to address these threats, implementation of legislation for the protection of manatees, and consistent enforcement of regulations to protect this population. Boating regulations, such as no-wake zones within areas of high manatee presence, as well as regulation of tourism boating activities, need to be implemented to reduce the threats to the species.

A systematic review, meta-analysis and meta-regression of the global prevalence of Toxoplasma gondii infection in wild marine mammals and associations with epidemiological variables

Toxoplasma gondii infection in wild marine mammals is a growing problem and is associated with adverse impacts on marine animal health and public health. This systematic review, meta-analysis and meta-regression estimates the global prevalence of T. gondii infection in wild marine mammals and analyzes the association between T. gondii infection and epidemiological variables. PubMed, Web of Science, Science Direct, China National Knowledge Infrastructure, and Wanfang Data databases were searched until 30 May 2021. Eighty-four studies (n = 14,931 wild marine mammals from 15 families) were identified from literature. The overall pooled prevalence of T. gondii infection was 22.44% (3,848/14,931; 95% confidence interval (CI): 17.29% - 8.04%). The prevalence in adult animals 21.88% (798/3119; 95% CI: 13.40 -31.59) was higher than in the younger age groups. North America had a higher prevalence 29.92% (2756/9243; 95% CI: 21.77 - 38.77) compared with other continents. At the country level, the highest prevalence was found in Spain 44.26% (19/88; 95%CI: 5.21 - 88.54). Regarding climatic variables, the highest prevalence was found in areas with a mean annual temperature >20°C 36.28% (171/562; 95% CI: 6.36 - 73.61) and areas with an annual precipitation >800 mm 26.92% (1341/5042; 95% CI: 18.20 - 36.59). The subgroup and meta-regression analyses showed that study-level covariates, including age, country, continent, and mean temperature, partly explained the between-study heterogeneity. Further studies are needed to investigate the source of terrestrial to aquatic dissemination of T. gondii oocysts, the fate of this parasite in marine habitat and its effects on wild marine mammals. This article is protected by copyright. All rights reserved.

Recent epidemiologic and clinical importance of Toxoplasma gondii infections in marine mammals: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. T. gondii causes mortality in several species of marine mammals, including threatened Southern sea otters (Enhydra lutris) and endangered Hawaiian monk seals (Monachus schauinslandi). Marine mammals are now considered sentinels for environmental exposure to protozoan agents contaminating marine waters, including T. gondii oocysts. Marine mammals also serve as food for humans and can result in foodborne T. gondii infections in humans. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, and genetic diversity of T. gondii infecting marine mammals in the past decade. The role of genetic types of T. gondii and clinical disease is discussed.

Leptospira spp. and Toxoplasma gondii in stranded representatives of wild cetaceans in the Philippines

Background

The stranding events of cetaceans in the Philippines provide opportunities for gathering biological information and specimens, especially from the pelagic forms. As part of an effort to monitor the health of wild cetaceans, this study detected Leptospira spp. and Toxoplasma gondii, causative agents of the emerging zoonotic diseases leptospirosis and toxoplasmosis respectively, in their stranded representatives. From October 2016–August 2018, 40 cetaceans (representing 14 species) that stranded nationwide were sampled for brain, cardiac muscle, skeletal muscle, kidney, and blood tissues, urine, and sera. These were subjected to molecular, serological, culture, and histopathological analyses to detect the target pathogens.

Results

T. gondii was detected in 20 (71%) of the 28 cetaceans with biological samples subjected to either molecular detection through RE gene amplification or IgG antibodies detection through agglutination-based serological assay. On the other hand, Leptospira was detected in 18 (64%) of 28 cetaceans with biological samples subjected to bacterial culture, molecular detection through 16S rDNA amplification, or IgM antibodies detection through ELISA-based serological assay.

Conclusions

There is the plausibility of toxoplasmosis and leptospirosis in cetacean populations found in the Philippines, however, acute or chronic phases of infections in sampled stranded individuals cannot be confirmed in the absence of supporting pathological observations and corroborating detection tests. Further studies should look for more evidences of pathogenicity, and explore the specific mechanisms by which pelagic cetacean species become infected by Leptospira spp. and T. gondii. As there is growing evidence on the role of cetaceans as sentinels of land-sea movement of emerging pathogens and the diseases they cause, any opportunity, such as their stranding events, should be maximized to investigate the health of their populations. Moreover, the role of leptospirosis or toxoplasmosis in these stranding events must be considered.

Parasite fauna of wild Antillean manatees (Trichechus manatus manatus) of the Andean Region, Colombia

BACKGROUND

Antillean manatees (Trichechus manatus manatus) are large herbivorous aquatic mammals living in limited areas of South, Central and North America. As with other aquatic mammals, Antillean manatees can be infected by a variety of protozoan and metazoan parasites, some of them with zoonotic potential, which affect not only their welfare but also population health status. Therefore, we conducted the first epidemiological survey in Colombian free-ranging Antillean manatees to estimate their actual gastrointestinal parasite status.

RESULTS

In total, 69 faecal samples were collected from free-ranging individual manatees during ecology field studies in the rivers Carare and San Juan and in two associated wetlands in the Andean region of Colombia. Parasite diversity encompassed six different endoparasite species. The highest prevalence was found for protozoan infections with Eimeria nodulosa (47.8%) and Eimeria manatus-like species (type A, B; 43.4%), followed by Entamoeba sp. (14.49%) and Giardia sp. (1.4%) infections. In addition, infections with the trematode Chiorchis fabaceus were detected at a high prevalence (33.3%). Molecular characterization of sirenian Eimeria species led to the distinction of three species, E. nodulosa and two E. manatus-like species (type A, B). Phylogenetic analyses indicated a host-specific adaptation of sirenian Eimeria species as previously reported for Eimeria species from other mammalian hosts.

CONCLUSIONS

This study provides the first record of Antillean manatee infection with Giardia and Entamoeba species in Colombia, representing two important anthropozoonotic parasite genera. This survey should serve as a baseline investigation for future monitoring on parasitic zoonoses in this mammal and encourage for investigations on their impact on both public health and wild manatee welfare.

Occurrence of endoparasites in wild Antillean manatees (Trichechus manatus manatus) in Colombia

The recognized impact of parasites in wildlife populations demands surveillance of endangered species like the Antillean manatees (Trichechus manatus manatus) in Colombia. We conducted a parasitological survey in four rescued sea cows in order to document the parasite diversity of this sirenian in the Caribbean wetland of Colombia and contribute to the molecular characterization of its trematodes. The flukes Chiorchis fabaceus, Nudacotyle undicola and the protozoans Eimeria manatus and E. nodulosa were identified in analysed faecal samples. For C. fabaceus and N. undicola, partial regions of ribosomal RNA genes were amplified and sequenced in order to infer their phylogenetic relations. The current study constitutes a new sirenian host (T. manatus manatus) record for the genus Eimeria and the trematode N. undicola.

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Gastrointestinal parasites of the Antillean manatee of Caribbean wetland in Colombia.

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First report of Eimeria species and N. undicola in the Antillean manatee (T. manatus manatus).

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First contribution to the phylogenetic knowledge of trematode parasites of manatees.

Investigating seagrass in Toxoplasma gondii transmission in Florida (Trichechus manatus latirostris) and Antillean (T. m. manatus) manatees

Toxoplasma gondii is a feline protozoan reported to cause morbidity and mortality in manatees and other marine mammals. Given the herbivorous nature of manatees, ingestion of oocysts from contaminated water or seagrass is presumed to be their primary mode of infection. The objectives of this study were to investigate oocyst contamination of seagrass beds in Puerto Rico and determine the seroprevalence of T. gondii in Antillean (Trichechus manatus manatus) and Florida (T. m. latirostris) manatees. Sera or plasma from Antillean (n = 5) and Florida (n = 351) manatees were tested for T. gondii antibodies using the modified agglutination test. No T. gondii DNA was detected via PCR in seagrass samples (n = 33) collected from Puerto Rico. Seroprevalence was 0%, suggesting a lower prevalence of T. gondii in these manatee populations than previously reported. This was the first study to investigate the potential oocyst contamination of the manatee diet, and similar studies are important for understanding the epidemiology of T. gondii in herbivorous marine mammals.

Disseminated toxoplasmosis Toxoplasma gondii in a wild Florida manatee Trichechus manatus latirostris and seroprevalence in two wild populations

Marine mammals are important indicators for ecosystem health and serve as sentinel species for infectious agents including zoonoses. Histological examination of tissues from a stranded Florida manatee Trichechus manatus latirostris revealed protozoal cysts in the cerebrum and intrahistiocytic tachyzoites in the liver and caudal mesenteric lymph node. Disseminated Toxoplasma gondii infection was confirmed by immunohistochemistry and sequencing of the nuclear ribosomal internal transcribed spacer region of formalin-fixed tissues. The lack of baseline information on Florida manatees' exposure to this pathogen prompted a study into the seroprevalence of T. gondii in 2 separate geographic habitats in Florida, USA, during the winters from 2011-2014. Serum was collected during routine health assessments of 44 apparently healthy manatees from Crystal River (n = 26) on the west central coast of Florida and Brevard County (n = 18) on the east coast of Florida. Serum was screened for detection of T. gondii immunoglobulin G (IgG) antibodies via the modified agglutination test. Two animals from Crystal River from 2011 and 2012 (7.7%) and one animal from Brevard County from 2011 (5.6%) tested positive for T. gondii antibodies. Overall seroprevalence for T. gondii was low in the 2 sampled populations and may reflect a low seroprevalence or animal susceptibility. However, continued monitoring of this pathogen in aquatic ecosystems is warranted due to both possible anthropogenic sources and zoonotic potential.

Association Between Toxoplasma gondii Exposure and Heart Disease: A Case-Control Study

Background

The parasite Toxoplasma gondii causes infections all around the world. Infections with T. gondii are systemic and the parasite can persist in the heart muscle. Very little is known about the impact of T. gondii on patients with heart disease. We determined the association between T. gondii exposure and patients suffering from heart diseases attending in a public hospital in Durango, Mexico; the association of T. gondii exposure with socio-demographic, behavioral, and clinical characteristics of these patients was also investigated.

Methods

Through a case-control study, we examined the seroprevalence of anti-T. gondii IgG and IgM antibodies in 400 patients with heart diseases and 400 age- and gender-matched controls using enzyme-linked immunoassays. In addition, we analyzed the association of patient characteristics as determined by a standardized questionnaire with T. gondii exposure by bivariate and multivariate analyses.

Results

Fifty-five (13.8%) of 400 patients and 32 (8.0%) of 400 controls had anti-T. gondii IgG antibodies (odds ratio (OR) = 1.83; 95% confidence interval (CI): 1.15 - 2.90; P = 0.01). High anti-T. gondii IgG levels (> 150 IU/mL) were found in 28 (50.9%) of the 55 positive cases and in 14 (43.8%) of the 32 positive controls (P = 0.51). Anti-T. gondii IgM antibodies were found in 13 (23.6%) of the 55 anti-T. gondii IgG positive patients and in 19 (59.4%) of 32 anti-T. gondii IgG positive controls (OR = 0.21; 95% CI: 0.08 - 0.54; P = 0.0008). Multivariate analysis showed that T. gondii exposure was positively associated with being born out of Durango State (OR = 2.93; 95% CI: 1.40 - 6.13; P = 0.004), and with consumption of alcohol (OR = 2.04; 95% CI: 1.01 - 4.12; P = 0.04).

Conclusions

Results obtained in this study indicate that T. gondii infection is associated with heart disease, and suggest that heart disease might be related with a chronic infection. This is the first report of an association of T. gondii exposure with alcohol consumption in this population. Results warrant for further research to determine the epidemiological impact of T. gondii exposure on patients with heart diseases. Risk factors associated with T. gondii exposure are critical to design future prevention strategies against T. gondii exposure.

Serum biochemistry reference intervals of live wild dugongs (Dugong dugon) from urban coastal Australia

BACKGROUND

Little is known about the baseline clinical pathology of the dugong (Dugong dugon), a vulnerable marine mammal found in tropical coastal marine systems.

OBJECTIVES

The purpose of the study was to collect and determine reference intervals (RI) for select serum biochemical variables for dugongs, and to analyze differences between males and females and different age groups.

METHODS

Reference intervals were established from 103 apparently healthy, wild-caught dugongs for 31 analytes using a Beckman Coulter AU400 Automated Chemistry Analyzer and an Olympus AU680 Chemistry-Immuno Analyzer.

RESULTS

Significant differences (P < .05) in some of the variables were found related to size class, sex, and pregnancy status. Adult dugongs had higher serum sodium, potassium, bicarbonate, glucose, and l-lactate concentrations and higher anion gap, compared to sub-adults. Male dugongs had higher triglyceride and l-lactate concentrations than females. Pregnant females displayed higher l-lactate levels compared to nonpregnant animals. Statistical differences in variables within the population contributed to better understanding of the physiologic differences between cohorts. Some serum biochemistry changes observed in this study here also potentially include some effects of pursuit on dugongs (eg, higher l-lactate); however, as all dugongs were subject to similar capture and handling, serum biochemistry RI should be considered as normal for captured dugongs.

CONCLUSIONS

The serum biochemical RI documented here are considered representative of a population of healthy captured dugongs. They provide a baseline for health surveillance of this and other dugong populations.