Giulia Simonato

Investigating the Determinants of Toxoplasma gondii Prevalence in Meat: A Systematic Review and Meta-Regression

Background Toxoplasma gondii is one of the most widespread parasites in humans and can cause severe illness in immunocompromised individuals. However, its role in healthy people is probably under-appreciated. The complex epidemiology of this protozoan recognizes several infection routes but consumption of contaminated food is likely to be the predominant one. Among food, consumption of raw and undercooked meat is a relevant route of transmission, but the role of different meat producing animal species and meats thereof is controversial. Objectives The aim of the present work is to summarize and analyse literature data reporting prevalence estimates of T. gondii in meat animals/meats. Data Sources We searched Medline, Web of Science, Science Direct (last update 31/03/2015). Eligibility Criteria Relevant papers should report data from primary studies dealing with the prevalence of T. gondii in meat from livestock species as obtained through direct detection methods. Meta-analysis and meta-regression were performed. Results Of 1915 papers screened, 69 papers were included, dealing mainly with cattle, pigs and sheep. Pooled prevalences, based on random-effect models, were 2.6% (CI95 [0.5–5.8]) for cattle, 12.3% (CI95 [7.6–17.8]) for pigs and 14.7% (CI95 [8.9–21.5]) for sheep. Due to the high heterogeneity observed, univariable and multivariable meta-regression models were fitted showing that the geographic area for cattle (p = 0.032), the farming type for pigs (p = 0.0004) and the sample composition for sheep (p = 0.03) had significant effects on the prevalences of Toxoplasma detected/estimated. Moreover, the role of different animal species was dependent on the geographic location of animals’ origin. Limitations Limitations were due mainly to a possible publication bias. Conclusions and Implications The present work confirms the role of meat, including beef, as T. gondii sources, and highlights the need for a control system for this parasite to be implemented along the meat production chain. Moreover, consumer knowledge should be strengthened in order to reduce the impact of disease.

Laboratory evidence on vector competence of the invasive mosquito Aedes koreicus [Hulecoeteomyia koreica] for Dirofilaria immitis

Aedes (Finlaya) koreicus is an exotic invasive mosquito detected for the first time in Italy in 2011. Little information on its vector competence for Dirofilaria immitis are available. The area where this species is now established (Veneto Region, north-eastern Italy) is endemic for dirofilariosis. In this study, Ae. koreicus specimens were experimentally infected with D. immitis to evaluate the development of filarial larval stages in different body districts. Aedes koreicus were reared under laboratory standard condition (temperature: 25 ± 1°C; relative humidity: 65 ± 5%; light-dark: 16-8 h). A test group (T) (n = 54 mosquitoes) and a control group (C) (n = 29 mosquitoes) were fed by an artificial feeding system (Hemotek™) using uninfected (in C) and naturally infected (in T) dog blood (3000 microfilariae/ml). Mosquitoes naturally dead and specimens killed at 1, 13, 16, 22 and 28 days post infection (dpi) were dissected; head, thorax and abdomen were examined separately. Five specimens (3 from T and 2 from C) were selected for histology. In addition, molecular confirmation by real time PCR for Dirofilariae were performed. Each larval stage was documented by pictures and videos. The experiment lasted 28 days. A total of 46 mosquitoes fed in T (85%) and 24 mosquitoes in C (83%) groups. In T, 11 mosquitoes were killed and 32 were recovered dead. The mosquito mortality rate in T was 52% during the first nine days, significantly higher compared to C (8%) (p < 0.01). In total, 31 mosquitoes (67%) were infected. The average of microfilariae, L1 (sausage stage) and L3 was 14.67, 8.56 and 3.15, respectively. Second stage larvae were observed only once (8 specimens on 13 dpi). First stage larvae were first observed on 3 dpi whereas L3 on 8 dpi. The latter were found in salivary glands and proboscis starting on 16 till 28 dpi. Aedes koreicus seems to be a suitable intermediate host for D. immitis. Despite the low initial number of microfilariae, the infective L3 stage was observed in all body districts including the proboscis. An high mosquito mortality occurred during the first days, nevertheless one third of them survived and became infective. This results show that Ae. koreicus may be involved in the natural cycle of D. immitis, increasing the risk of exposure for dogs and humans.

PCR-based assay for the mitochondrial cox1 specific amplification of Eucoleus böhmi

Eucoleus böhmi (syn. Capillaria boehmi) is a trichuroid nematode affecting the epithelium of the nasal turbinates, frontal and paranasal sinuses of wild and domestic canids. Knowledge of the geographic distribution of nasal eucoleosis is fragmentary, despite the infection has been described from Europe and North America. Moreover, gaps exist in information available on the importance of the disease in canine clinical practice. The lack of knowledge on E. böhmi is likely due to limitations inherent to diagnostic methodologies. The aim of the present work was to assess a PCR-based assay instrumental to the amplification of a species-specific region of the mitochondrial DNA (mtDNA) gene encoding for the subunit 1 (cox1) gene of E. böhmi. Adult worms of E. böhmi from red foxes and dogs from Norway, Serbia and Italy and individual fecal samples from naturally infected dogs from Italy were included in the study. Stool samples from dogs negative for E. böhmi, but positive for other common parasites in both single and mixed infections, and adult stages of common dog parasites, were used to assess the specificity of this genetic assay. Using the panel of faecal samples, the assay showed a sensitivity of 85.14% and a specificity of 100%.

Mitochondrial haplotypes of Aelurostrongylus abstrusus and Troglostrongylus brevior (Nematoda, Metastrongyloidea) from domestic and wild felids

The lungworm Aelurostrongylus abstrusus is the most important respiratory parasite of domestic cats. Pulmonary aelurostrongylosis has been reported in wild felids, though unequivocally evidence of wildlife infection by A. abstrusus is scant. Recently, Troglostrongylus brevior, a lungworm usually infecting wild felids, has been described in domestic cats from Mediterranean areas. The present work evaluates the sequence variation of an informative region within the gene encoding the mitochondrial cytochrome c oxidase subunit 1 of A. abstrusus and T. brevior, in order to provide novel information on the genetic make-up of these lungworms. Parasitic stages of A. abstrusus and T. brevior were collected from domestic and wild hosts (i.e., domestic cat, European wildcat, caracal, serval, and lion) from Italy, Greece, and South Africa. Five (HI-HV) and four (HI-HIV) haplotypes were recorded for A. abstrusus and T. brevior, respectively, mostly shared between domestic and wild felids in different geographical areas. The phylogenetic analysis showed that all haplotypes of A. abstrusus and T. brevior clustered as monophyletic groups with a strong nodal support, indicating that all haplotypes identified were distinct from each other. All sequence types represent two distinct species, A. abstrusus and T. brevior, and these genetic convergences are also detected within and among populations of these nematodes, irrespective of their hosts and geographical origin. The occurrence of A. abstrusus and T. brevior haplotypes in different hosts from the same regions and between different countries indicates that the same lungworm populations circulate in domestic and wild hosts under the same routes of transmission.

Zoonotic intestinal parasites and vector-borne pathogens in Italian shelter and kennel dogs

This study investigated the presence of zoonotic parasites and vector-borne pathogens in dogs housed in kennels and shelters from four sites of Italy. A total of 150 adoptable dogs was examined with different microscopic, serological and molecular methods. Overall 129 dogs (86%) were positive for one or more parasites and/or pathogens transmitted by ectoparasites. Forty-eight (32%) were positive for one infection, while 81 (54%) for more than one pathogen. The most common zoonotic helminths recorded were hookworms, roundworms and Capillaria aerophila, followed by mosquito-borne Dirofilaria spp. and Dipylidium caninum. One hundred and thirteen (77.9%), 6 (4.1%) and 2 (1.4%) dogs were positive for Rickettsia spp., Leishmania infantum and Anaplasma spp., respectively. The results show that dogs living in rescue facilities from the studied areas may be infected by many zoonotic internal parasites and vector-borne pathogens, and that control measures should be implemented.

Toxoplasma gondii infection and food consumption: A systematic review and meta-analysis of case-controlled studies

ABSTRACT Background: Toxoplasmosis is a zoonotic disease causing severe symptoms in pregnant women and immunocompromised individuals. On average, worldwide, around 30% of people are seropositive. The oral transmission route is of great significance and food, particularly meat, is an important transmission vehicle for T. gondii. However, the role of different food matrices is debated. Objectives: The aim of this review was to assess the risk of humans developing acute T. gondii infection via the foodborne route. Study eligibility criteria: Case-control studies including acute cases of T. gondii infection were included after literature searches, without time limits, in several databases. All studies estimating the risk of acquiring T. gondii infection after consumption of specific food categories were included. Results: Three risk factors proved to be significantly associated with acute T. gondii infection in humans: consumption of raw/undercooked meat, Odds Ratio (OR) 3.44 (1.29–9.16), consumption of raw/undercooked beef, OR 2.22 (1.57–3.12), and consumption of raw/undercooked sheep meat, OR 3.85 (1.85–8.00). Consumption of raw/undercooked pork, raw eggs, and unpasteurized milk proved to be non-significant risk factors. Limitations: Limitations in the present review and meta-analysis are due to the low number of case-control studies available for analysis and the lack of a search strategy targeting gray literature. Conclusion: Consumption of raw/undercooked beef and sheep meat are important risk factors for T. gondii infection. Their consumption should be avoided in order to prevent toxoplasmosis, particularly by those in at-risk categories, including pregnant women. The review protocol is registered in PROSPERO database (CRD42016043295).

Microfilaricidal efficacy of a single administration of Advocate® (Bayer Animal Health) in dogs naturally infected with Dirofilaria immitis or Dirofilaria repens

The present study evaluated the microfilaricidal efficacy of a single application of the spot-on containing imidacloprid 10%/moxidectin 2.5% (Advocate(®), Bayer Animal Health) in dogs naturally infected either by Dirofilaria immitis or Dirofilaria repens. Dogs living in north-eastern and central-southern Italy, endemic for D. immitis and D. repens respectively, were randomly screened. Sixteen animals, eight infected with D. immitis and eight with D. repens, and fulfilling inclusion criteria were enrolled. Dogs infected with D. immitis received an adulticide treatment prior to the study and Advocate(®) 3 weeks after. The animals were divided in blocks of two (1:1, T1:T2) animals each, where Day 0 (D0) had an interval of 15days to compare T2 vs. T1 dogs during the first fortnight of examination (i.e. T2 dogs acted as control animals at each examination). At baseline (Days -15 and 0 for T2 and T1 dogs, respectively) the animals had a range of microfilaraemia of 180-99.700mff/ml (D. immitis) and 60-750 mff/ml (D. repens). All animals received a topical administration of Advocate(®) at D0 and were examined for microfilariae with microscopic and molecular tests at D15, D30, D60 and D90. All animals scored negative for mff at the first control post-treatment and throughout the study, with the exception of two D. immitis- infected animals that had a 2 mff/ml count at D15, and then become negative from Day 30 onwards. No adverse events were observed. The present study demonstrates the safety and the high microfilaricidal efficacy (99.97% and 100% for D. immitis and D. repens, respectively) of a single dose of moxidectin contained in Advocate(®) in naturally infected dogs.

Field Trial To Evaluate Two Different Procedures For Monitoring the Efficacy of Aquatain® Against Culex pipiens and Aedes albopictus IN CATCH BASINS

ABSTRACT Aedes albopictus and Culex pipiens are commonly distributed in Italy and represent the main species found in catch basins. The application of a silicone-based film (e.g., Aquatain®) is a new tool recently introduced for treating catch basins. While the efficacy of Aquatain has been experimentally demonstrated, its use is still lacking an appropriate monitoring procedure. The present study compared the differences in the efficacy of treatment assessment between a newly developed floating system (FS), which was designed to collect emerging adults, with the standard dipper procedure, used for estimating the abundance of mosquito larvae. Forty catch basins, half treated with Aquatain and half untreated (control basins), were monitored weekly using dipper (10 treated + 10 control basins) or FS (10 + 10) 5 times after 2 subsequent treatments. Both monitoring procedures recorded high percentages of larvae and adult reduction for the 1st 1−3 wk after treatments, confirming the simultaneous activity of Aquatain against all stages of mosquitoes. Differences in adult emergence were recorded also when monitoring of larvae was ineffective, suggesting that the newly developed FS is a promising method for assessing the efficacy of monomolecular films in catch basins.