Molecular Survey on Toxoplasma gondii and Neospora caninum Infection in Wild Birds of Prey Admitted to Recovery Centers in Northern Italy

Neospora caninum antibodies in bulk tank milk from dairy cattle herds in Italy in relation to reproductive and productive parameters and spatial analysis

Among the available diagnostic techniques, antibody detection in bulk tank milk (BTM) represents a useful tool to estimate and monitor Neospora caninum herd prevalence. To evaluate the prevalence of N. caninum and the effect of parasite infection on herd performances, BTM samples collected from 586 dairy herds located in one of the largest dairy production areas in Italy (Lombardy) were analyzed by an indirect ELISA to detect anti-N. caninum specific antibodies. Generalized linear models (GLMs) were developed. A purely spatial analysis scanning for clusters with high or low rates for N. caninum using the Bernoulli model was performed. A maximum entropy approach was used to estimate the probability of distribution of the parasite based on occurrence records together with environmental variables. Overall, 180 herds resulted positive for N. caninum antibodies on bulk tank milk (P = 30.7 %). A higher risk of seropositivity was evidenced in the provinces of Milano, Cremona, Brescia, and Bergamo (P = 32-40 %); a lower risk was evidenced in Lodi, Pavia, and Mantova (P = 13-24 %). A higher risk of seropositivity was revealed for small-medium farms (101-300 animals) (O.R.=2.8) and for older animals with more than 4 years (O.R.=4.4). Regarding the effect of N. caninum infection on herd performances, the number of inseminations for conception was higher (> 3 inseminations), and the period from calving to conception was longer (> 150 days) for positive farms (O.R.=2.0 and O.R.=2.3, respectively); besides, lower head daily milk production (<20 kg and 21-25 kg) and mature equivalent milk yield (<11,000), and somatic cell counts higher than 300,000 cells/ml were observed for N. caninum positive herds (O.R.=0.4, O.R.=0.4 and O.R.=1.9 respectively). The geographical distribution of N. caninum positive farms with the highest level of probability covers the central sector of the Po Plain where a significant cluster for high risk of parasite infection was shown by spatial scan statistic and Maximum entropy ecological niche modelling. A further significant cluster of low risk occurred in the southern. The climatic and environmental variables with the highest training gain when used in isolation resulted altitude, land use/land cover, and other variables related to temperature and precipitation. Neosporosis is widely distributed in Italian dairy herds and an impact of the parasite on herd performances could be hypothesized. Even if the role of N. caninum in alterations of reproductive and productive parameters should be further explored, veterinarians and farmers should be aware of neosporosis, and control plans should be adopted.

Global prevalence and risk factors associated with Toxoplasma gondii infection in wild birds: A systematic review and meta-analysis

A systematic review and meta-analysis were performed to identify the global prevalence and factors associated with Toxoplasma gondii infection in wild birds. Six bibliographic databases (Chinese National Knowledge Infrastructure, VIP Chinese Journal Database, Wanfang Data, PubMed, Web of science and ScienceDirect) were searched from inception to February 2023. The search yielded 1220 records of which 659 articles underwent full-text evaluation, which identified 49 eligible articles and 16,030 wild bird samples that were included in the meta-analysis. The estimated pooled global prevalence of T. gondii infection in wild birds was 16.6%. Out of the variables tested, publication year after 2020 and climate type were significantly associated with T. gondii infection (P<0.01). Our data indicate that the prevalence of T. gondii in wild birds can be influenced by epidemiological variables. Further research is needed to identify the biological, environmental, anthropogenic, and geographical risk factors which impact the ecology and prevalence of T. gondii in wild birds.

Serological Prevalence of Toxoplasma gondii, Neospora caninum, and Sarcoptes scabiei var. suis in Wild Boars (Sus scrofa) Hunted in a Highly Anthropized Area in Italy

Due to the increasing expansion into urban and rural areas, wild boars represent a potential source of infection with zoonotic and animal-specific parasites for both humans and animals. Therefore, the aim of this study was to investigate the serological prevalence to Toxoplasma gondii, Neospora caninum, and Sarcoptes scabiei var. suis in blood samples from wild boars (Sus scrofa) hunted in an anthropized area in Italy. Enzyme-linked immunosorbent assay (ELISA) tests were used to detect antibodies anti-T. gondii and anti-S. scabiei and an immunofluorescence antibody test (IFAT) for antibodies anti-N. caninum. 81 out of 128 wild boars (P = 63.3%) resulted positive for at least one of the three parasites. 68 of them were seropositive to T. gondii (P = 53.1%) and 14 to N. caninum (P = 10.9%). 9 wild boars resulted seropositive to S. scabiei var. suis (P = 7.0%). Sampling season was the only significant risk factor related to S. scabiei var. suis seroprevalence (OR = 7.8). The high occurrence of T. gondii supports the role of this species as a source of infection for other animals and humans. Furthermore, the serological prevalence of N. caninum and S. scabiei var. suis in wild boars from the study area characterized by the presence of numerous dairy cattle and pig farms is relevant to demonstrate its suitability for the circulation of these parasites both in domestic and wild species.

Molecular Survey of Toxoplasma gondii in Wild Mammals of Southern Italy

Systematic wildlife surveillance is important to aid the prevention of zoonotic infections that jeopardize human health and undermine biodiversity. Toxoplasma gondii is an opportunistic zoonotic protozoan that can infect all endothermic vertebrates, causing severe disease in immunocompromised humans and cases of congenital transmission. Humans can be infected by ingestion of raw meat containing bradyzoites or water contaminated by oocysts. In our study, we assessed the potential circulation of Toxoplasma gondii in wild mammals by performing surveillance in the Campania region (southern Italy) and surveyed its presence from 2020 to 2022 within the framework of the Regional Plans for Wildlife Surveillance. In detail, 211 individuals belonging to five wild mammals (wolf, fox, wild boar, badger, and roe deer) underwent necropsy and the organs were analyzed by real-time PCR for the detection of the parasite. Toxoplasma gondii was found in 21.8% (46/211) of the subjects examined. No statistically significant differences were noticed between the prevalence and the host’s trophic level or age, rejecting the hypotheses that Toxoplasma gondii will have a higher prevalence in top predators and adult individuals, respectively. Our work emphasized the high circulation of Toxoplasma gondii in wildlife and remarked on the critical role of anthropized areas where domestic cats and wildlife may come into contact, urging a systematic surveillance.

The Dangerous Side of Being a Predator: Toxoplasma gondii and Neospora caninum in Birds of Prey

Toxoplasma gondii and Neospora caninum are apicomplexan protozoa of major concern in livestock and T. gondii is also considered one of the major threats and a public health concern. These protozoa have a wide range of intermediate hosts, including birds. The present work aimed to assess the prevalence of these cyst-forming parasites in migratory and sedentary birds of prey. The skeletal muscle and myocardium of 159 birds of prey from Central Italy, belonging to 19 species and recovered across 6 Wildlife Recovery Centers/Care structures along the Italian migratory route, were collected specifically for molecular (PCR) and for histopathological analysis to detect T. gondii and N. caninum. For the molecular analysis, genomic DNA was extracted. The DNA was tested by sequence typing, targeting GRA6, 529 bp repeated element, B1, PK1, BTUB, SAG2, alt.SAG2, and APICO genes for T. gondii and to end-point PCR targeting NC5 gene for N. caninum. Thirty-seven out of the one hundred and fifty-nine analyzed samples tested positive for T. gondii with a prevalence of 23.27% and nine for N. caninum, with a prevalence of 5.66%. Thirty-two sequences were obtained from the thirty-seven isolates of T. gondii. Among these, 26 presented alleles compatible with type I strain in 1 or more loci, 4 with type II strain and 2 consisted of atypical strains. Toxoplasma gondii genetic variability in birds of prey confirms previous findings of wildlife as reservoirs of atypical strains. Results from the histology showed few protozoal tissue cysts in skeletal muscle (n. 4) and hearts (n. 2).

Molecular characterization and genotyping of Toxoplasma gondii in free-living animals in Iran: Effect of One Health

To understand the transmission of Toxoplasma gondii, this parasite's genetic diversity distribution in free-living hosts is essential. This research's objective is the molecular genotyping of T. gondii isolates from the brain and muscles of Columbidae, Corvidae, Rattus, and Felidae of Mianeh County, East-Azerbaijan Province, Northwest Iran. Three hundred fifty samples were taken. For the genotyping of T. gondii, the GRA6 gene was amplified and digested by the Tru1I (MseI) enzyme. Results of RFLP were confirmed by sequencing and phylogenetic analysis. In total, 52%, 34%, 24%, and 50% of Columbidae, Corvidae, Rattus, and Felidae were positive for T. gondii DNA, respectively. All isolated Columbidae were identified as genotype III (100%). Also, 94.1% and 5.9% of Corvidae isolates, 84.4% and 15.6% of the Rattus isolates, and 51.7% and 48.3% of the Felidae isolates belonged to genotypes III and II, respectively. This study is the first to evaluate genetic similarity and phylogenetic analysis between many definitive and intermediated hosts in northwestern Iran. The finding indicates that the T. gondii cycle is maintained among these hosts. As a result, their presence in the environment can be a risk factor for transmitting the infection to humans. Due to demographic and geographic differences in various regions, further studies are required to determine the genetic population structure.

Seroprevalence and risk factors of Toxoplasma gondii and Neospora caninum infection in black goats in Yunnan Province, Southwestern China

Toxoplasma gondii and Neospora caninum are two obligate intracellular protozoan parasites that can cause reproductive failure and production losses. To date, there is no data of T. gondii and N. caninum seroprevalence in black goats in Yunnan Province, southwestern China. In the present study, a total of 734 serum samples were collected from black goats in four different counties of Yunnan Province. 734 and 590 serum samples were examined for antibodies against T. gondii and N. caninum by using MAT and indirect ELISA, respectively. A total of 123 and 76 samples were T. gondii-positive and N. caninum-positive, respectively. The overall seroprevalence of T. gondii in black goats was 16.76% (123/734, 95% CI: 14.06-19.46) with the titer ranged from 1:25 to 1:3200. The seroprevalence of N. caninum was 12.88% (76/590, 95% CI: 10.18-15.58). There was significant difference in seroprevalence of N. caninum in different regions (P < 0.01, χ² = 30.63) and age groups (P < 0.05, χ² = 11.85). Significant differences in seroprevalence of T. gondii were observed in different regions (P < 0.05, χ² = 9.21) and different gender groups (P < 0.01, χ² = 12.29). Results of seroprevalence of T. gondii and N. caninum indicated that T. gondii and N. caninum were prevalent parasites in black goats in Yunnan Province. This is the first report of seroprevalence of T. gondii and N. caninum in black goats in Yunnan Province. The results of this study indicated that some measures should be taken to control these two parasites and to reduce economic losses to the livestock industry in Yunnan Province.

Toxocara cati and Toxoplasma gondii in French Birds of Prey

Parasites have developed many strategies to ensure their development, multiplication, and dissemination, including the use of reservoir hosts that are often nondomesticated species. Despite drastic reductions in their populations, wild birds remain widespread worldwide and could constitute some of these reservoirs. We focused on the identification of wild bird species harboring parasite stages in their muscles. Breast muscles of 327 birds of 27 different species were collected at three different sites in France. After artificial digestion, isolated nematode larvae were identified by PCR sequencing or restriction fragment length polymorphism (PCR-RFLP). Toxocara cati was identified mainly in birds of prey. The presence of anti-Toxoplasma antibodies was investigated by modified agglutination test on muscle fluids. Anti-Toxoplasma antibodies were detected in 65 out of 166 samples from various bird species. Avifauna, particularly birds of prey, could help on the surveillance of parasite circulation and play a role as sentinel species.

The Utility of Serological Analysis for Neospora caninum Infection in Dairy Cattle Farms Management: Serological Investigation and Evaluation of the Effects on Reproductive and Productive Performances in Two Study Herds in Northern Italy

Simple Summary

Among infectious agents triggering reproductive disorders in cattle, Neospora caninum, an obligate intracellular protozoan parasite, is a major cause of abortion in cows worldwide. A serosurvey was designed in two cattle herds, both located in northern Italy and with similar reproductive management features, recruited as a case study. The clinical outcome and the effects on herd performances were evaluated in association with the seropositivity to N. caninum. This study showed that the integration of serological analysis results for N. caninum, the reproductive and productive parameters, and the information on herd performances, could give indications for the application of control strategies.

Abstract

Neospora caninum is recognized as a major cause of abortion in cattle, determining economic losses, particularly in dairy industries. To evaluate the impact of neosporosis on herd efficiency, and to understand how the serological analysis for N. caninum is explicative of the farm picture, an epidemiological study was designed in two dairy farms recruited as a case study. Blood samples were collected from 540 animals, including cows and heifers over 12 months, and analyzed by an indirect immunofluorescent antibody test with subsequent antibody titration. Overall, 94 animals (17.4%) were identified as positive to N. caninum antibodies (15.5% and 18.5% in Farm 1 and Farm 2), with differences between the farms concerning the antibody titers (Chi-square, p-value = 0.04), particularly in cows (Chi-square, p-value = 0.018). Consequently, a different pattern of abortion episodes was depicted in the two investigated farms. Considering reproductive and productive performances, the number of inseminations necessary to make an animal pregnant was higher in seropositive cows (2.4 and 2.9 in Farm 1 and 2, respectively) than in seronegative ones (2.1 and 2.4 in Farm 1 and 2, respectively). Similarly, particularly in Farm 1, the number of days in milk of not-pregnant cows was higher in seropositive (167.7) than seronegative animals (133.4). Moreover, although the association between N. caninum infection and milk production is still unclear, both the daily milk production and the 305-mature equivalent milk yield were lower in seropositive (31.02 and 11,838.94) than seronegative cows (33.59 and 12,274.88) in Farm 1; an opposite pattern was otherwise depicted in Farm 2. The study showed that even if N. caninum circulated equally in the two herds, the dynamics of the parasite infection and its outcome may be different, also depending on the specific situation of the farm. In this way, the integration of serological analysis for N. caninum, the reproductive and productive parameters, and the information on herd performances, could give specific indications for the application of control strategies.

Prevalence of Neospora caninum antibodies in fattening pigs and sows from intensive farms in northern Italy

Neospora caninum (Apicomplexa, Sarcocystidae) is a major cause of reproductive failure in cattle. In pigs, only a few studies investigated the effects of this parasite on reproductive efficiency. Considering the relevance of swine farms in northern Italian regions, an epidemiological survey was designed to investigate the spread of N. caninum infection. Three hundred seventy fattening pigs and sows from 23 intensive farms in Lombardy were sampled. Sera were analyzed by a commercial immunofluorescence antibody test. Statistical analysis through univariate and multivariate generalized linear models was conducted to detect farm management practices enhancing the risk of infection. At the farm level, 52.1% (12/23) of the selected farms, 72.7% housing sows and 40% fattening pigs, scored positive. At the individual level, 25 animals (25/370, P = 6.7%) were positive to N. caninum antibodies: one fattening pig and two sows showed an antibody titer of 1:100, and in two sows, an antibody titer of 1:400 and 1:6400 was evidenced. A higher seroprevalence was detected in sows (17/151, P = 11.2%) if compared to fattening pigs (8/219, P = 3.6%) (OR = 1.19, P value = 0.000 in sows). Moreover, a higher seroprevalence was recorded in farms with low and moderate sanitary score (P = 100% and P = 64.2%, respectively) if compared to farms with high sanitary score (P = 22.2%) (OR = 1.24, P value = 0.007 in score = 1 and OR = 1.10, P value = 0.050 in score = 2). This study provides the first data on the circulation of N. caninum in intensive swine farms in Italy, demonstrating the spread of the parasite in fattening pigs and sows in Lombardy region.

Editorial for the Special Issue "Parasitic Diseases from Wild Animals with Emphasis on Zoonotic Infections"

The present Editorial intends to briefly describe the findings published in the Special Issue, "Parasitic diseases from wild animals with an emphasis on zoonotic infections". Prevalence data or diagnostic techniques were the focus of several zoonotic parasites transmitted from wildlife, including the protozoa Toxoplasma, Cryptosporidium, Giardia, Blastocystis and Leishmania, and the helminths Echinococcus and Anisakis.