Toxocara canis- and Toxocara cati-Induced Neurotoxocarosis is Associated with Comprehensive Brain Transcriptomic Alterations

Toxocara canis and Toxocara cati are globally occurring zoonotic roundworms of dogs and cats. Migration and persistence of Toxocara larvae in the central nervous system of paratenic hosts including humans may cause clinical signs of neurotoxocarosis (NT). As pathomechanisms of NT and host responses against Toxocara larvae are mostly unknown, whole-genome microarray transcription analysis was performed in cerebra and cerebella of experimentally infected C57Bl/6J mice as paratenic host model at days 14, 28, 70, 98, and 120 post-infection. Neuroinvasion of T. cati evoked 220 cerebral and 215 cerebellar differentially transcribed genes (DTGs), but no particular PANTHER (Protein ANalysis THrough Evolutionary Relationships) pathway was affected. In T. canis-infected mice, 1039 cerebral and 2073 cerebellar DTGs were identified. Statistically significant dysregulations occurred in various pathways, including cholesterol biosynthesis, apoptosis signaling, and the Slit/Robo mediated axon guidance as well as different pathways associated with the immune and defense response. Observed dysregulations of the cholesterol biosynthesis, as well as the Alzheimer disease-amyloid secretase pathway in conjunction with previous histopathological neurodegenerative findings, may promote the discussion of T. canis as a causative agent for dementia and/or Alzheimer’s disease. Furthermore, results contribute to a deeper understanding of the largely unknown pathogenesis and host-parasite interactions during NT, and may provide the basis for prospective investigations evaluating pathogenic mechanisms or designing novel diagnostic and therapeutic approaches.

NGHIÊN CỨU ĐẶC ĐIỂM LÂM SÀNG, CẬN LÂM SÀNG Ở NGƯỜI BỆNH ẤU TRÙNG GIUN ĐŨA CHÓ, MÈO TẠI TRUNG TÂM MEDIC THÀNH PHỐ HỒ CHÍ MINH NĂM 2018 - 2019

Bệnh nhiễm Toxocara spp. là bệnh ký sinh trùng lây truyền từ động vật sang người do sự di chuyển của ấu trùng Toxocara canis ở chó và Toxocara cati ở mèo, đang trở thành vấn đề sức khỏe cộng đồng quan trọng. Việc chẩn đoán bệnh ấu trùng giun đũa chó, mèo ở người còn gặp nhiều khó khăn do biểu hiện lâm sàng không đặc hiệu, có thể dẫn đến bệnh kéo dài và gây các biến chứng. Mục tiêu: Nghiên cứu nhằm mô tả triệu chứng lâm sàng, các thay đổi cận lâm sàng ở người bệnh ấu trùng giun đũa chó, mèo. Phương pháp: Nghiên cứu mô tả cắt ngang và phân tích. Kết quả: Tuổi trung bình là 41 ± 15 tuổi, nhóm tuổi 20 - < 60 tuổi chiếm 75,9%. Tỷ lệ phân bố giới nữ nhiều hơn nam. Các triệu chứng thường gặp nhất ở da, niêm mạc (77,5%), sau đó là các biểu hiện thần kinh (35,0%), tiêu hóa (31,7%) và hô hấp (21,7%). Tất cả bệnh nhân đều có tăng số lượng bạch cầu ái toan trong máu ngoại biên nhưng 91,7% tăng mức độ nhẹ (từ 500 - < 1.500 tế bào/mm3). Nồng độ IgE toàn phần trong huyết thanh trung bình là 764,7 ± 630,6 IU/mL, 43,3% có IgE tăng dưới 4 lần giới hạn bình thường (từ 130 - < 520 IU/mL). Mật độ quang của anti-Toxocara spp. IgG trung bình là 1,51 ± 0,85, phân bố giá trị từ 0,36 - 3,50. Kết luận: Triệu chứng lâm sàng bệnh ấu trùng giun đũa chó, mèo ở người đa dạng, biểu hiện ở nhiều cơ quan. Bạch cầu ái toan trong máu ngoại biên, nồng độ IgE toàn phần huyết thanh và kháng thể kháng Toxocara spp. IgG là các thông số cận lâm sàng quan trọng chẩn đoán bệnh ấu trùng giun đũa chó, mèo ở người.

Prevalence, Risk Factors and Genotypes of Giardia duodenalis in Sheltered Dogs in Tuscany (Central Italy)

In sheltered dogs, the prevalence of Giardia duodenalis is frequently high and may include potential zoonotic genotypes. The prevalence, genotypes and potential risk factors of G. duodenalis were assessed in 168 dogs from four kennels (Pistoia, Prato, Florence, Valdarno) in Tuscany, central Italy and compared with data from previous Italian studies. The prevalence of other intestinal parasites was also investigated. Individual dog faecal samples collected from each kennel were examined by parasitological techniques and a rapid immunoassay for the detection of G. duodenalis and Cryptosporidium faecal antigens. On Giardia-positive samples, molecular analysis was performed for genotype identification. Overall, 69 dogs scored positive for G. duodenalis (41%), but significant differences (p ≤ 0.05) were found among the four kennels and sampling seasons. The potentially zoonotic assemblages A and B and the canine-specific assemblage C (Pistoia: A-AII, B, C; Prato: A-AII, B; Florence: A-AII; Valdarno: A and C) were identified. Toxocara canis (8.9%), Trichuris vulpis (3.6%), hookworms (1.19%) and Cryptosporidium sp. (0.6%) were also identified. The high prevalence of G. duodenalis and the identification of potentially zoonotic genotypes in all examined kennels underline the need to improve routine parasite monitoring and control measures and to provide insights into the zoonotic potential of G. duodenalis.

Toxocariasis affecting brain stem and skull base

Background Toxocariasis is a helminthic infection caused by a nematode that mainly affects populations in tropical and subtropical latitudes. Humans are potential paratenic hosts, and clinical disease occurs as a result of parasite migration through intestinal tissue. We present a clinical case of otorhinolaryngological affectation by Toxocara canis. Case presentation A 60-year-old male from Ecuador, resident in Spain for 5 years, evaluated in the emergency department for presenting headache, otorrhea and left ear pain. Computed tomography (CT) and magnetic resonance imaging (MRI) reported a large mass of the nasopharynx with infiltration of the skull base, intracranial extension and a lesion in the left pons without being able to exclude metastases. Two Functional Endoscopic Sinus Surgery (FESS) biopsies were negative for malignancy. Despite not meeting the diagnostic criteria established by the existing literature, the clinical and radiological presentation, the presence of risk factors, a positive serology for Toxocara canis (IgGELISA) and the absence of alternative diagnosis were considered sufficient criteria to establish toxocariasis with inflammatory lesions in the nasopharynx and pons as the most probable diagnosis. Treatment with albendazole (400 mg / 12 h) and corticosteroids (1 mg / kg for 5 days) was started and continued for one month. Post treatment negative serology, and MRI and CT post treatment controls were performed after one year, both showing a decrease in lesion of the clivus as well as the pons. Conclusions With the appropriate personal history, toxocariasis should be included in the differential diagnosis of infiltrating lesions of the skull base with a negative study of tumor histology. Albendazole treatment has been shown to control and cure the disease.

Seroprevalence of Toxocara Infection among Asthmatic Children in Shiraz City, Southern Iran

Background: Human toxocariasis is caused by Toxocara canis and T. cati, the nematodes in the intestine of dogs and cats, respectively. Since the association between asthma and toxocariasis is controversial, the aim of the present study was to investigate the seroprevalence of Toxocara infection among asthmatic children in comparison with healthy children. Methods: This case-control study was conducted on 92 asthmatic and 91 healthy children aged 1-16 years old in Shiraz City, Southern Iran in 2019-2020. The serum samples were tested for IgG anti-Toxocara antibodies by ELISA method using the T. canis larval excretory-secretory (E/S) antigens. The collected data were analyzed using SPSS software. Results: The seroprevalence of toxocariasis in asthmatic patients was higher than the healthy children with no significant difference in Toxocara seropositivity between two groups (9.8% vs 8.8%, P = 0.817). The association between Toxocara infection and variables such as gender and age were not statistically significant. Conclusion: There was no significant association between toxocariasis and childhood asthma. Further study on different regions such as urban and rural areas with a large sample size and using questionnaire for considering risk factors of asthma and toxocariasis is recommended.