Acta tropica最新文献

Nearly 32 % of sand fly species recorded in Mexico are related to Leishmania transmission. A correct morphological identification of sand flies is essential to improve epidemiological and control strategies. Wing geometric morphometrics (GM) has proven to be a complementary tool for classical taxonomy, allowing us to explore variations in structure and shape between species. This study evaluated whether the use of wing morphometric traits aids to identify vector sand fly species independently of their geographic distribution. The specimens were identified morphologically using specialized keys, and the right wings were analyzed using 17 landmarks. Principal Component Analysis, Canonical Variate Analysis, and Mahalanobis distances were calculated to quantify morphological differentiation. A total of 305 specimens from nine species were analyzed. Procrustes ANOVA showed significant differences (P < 0.0001) in shape and size for species, as well as significant differences across their distribution between populations of Lutzomyia cruciata (P < 0.0001) and Psathyromyia shannoni (P < 0.0001), respectively. The use of GM tools was effective to separate species at interspecific and intraspecific level, evidencing population differences in vector sand fly species that could favor the transmission of Leishmania.

Scrub typhus (ST) is an emerging public health concern in India. Despite being treatable, 20-30 % of acute febrile illnesses (AFI) progress to encephalitis in endemic regions. This study aimed to identify early markers for encephalitis development in children hospitalized with AFI and positive Orientia tsutsugamushi (Ots) serology. This prospective cohort study was conducted during January-December 2018, involved AFI patients (age ≤ 16 years) tested positive for IgM antibodies against Ots. These patients were followed up prospectively to monitor the development of encephalitis. The clinical and biochemical data from ST-AFI cases developed encephalitis were compared with ST-AFI cases did not develop encephalitis. Univariate and multivariate logistic regression analysis were used to determine predictors of encephalitis. Total 41 out of 190 (21.6 %) ST-AFI patients progressed to encephalitis. The multivariate regression analysis identified initiation of antibiotic therapy after more than 5 days from illness onset (OR 4; 95 % CI [1.4-11.6]), vomiting (>3 episodes) (OR: 10.9; 95 % CI [2.3-51.4]), Glasgow Coma Scale (9-12) (OR 6; 95 %CI [1.9-19]), calcium level (≤8 mg/dL) (OR 6.1 95 % CI [1.1-32.6]), serum creatinine (>1 mg/dL) (OR 16.8, 95 % CI [1.5-191.9]), and oxygen support requirement (OR 19.5, 95 % CI[6.4-59.3]) at admission as predictor of encephalitis in ST-AFI cases. The sensitivity and specificity of model was 67.50 % and 93.96 % respectively, Hosmer-Lemeshow test (χ2 = 8.82, P = 0.3584), and an area under the ROC curve of 0.9514. Study found initiation of antibiotic more than 5 days after illness onset, multiple vomiting episodes, low GCS, hypocalcaemia, high creatinine, and oxygen need as predictors of encephalitis in ST-AFI patients.

Introduction: Brucellosis is still a significant emerging threat to public health, as it can infect humans, wild, domestic animals, and livestock. Hence, the current study aims to determine the frequency of canine brucellosis (CB), its relationship with clinical findings and reproductive disorders in kennel and farm dogs, and its importance on public health.

Materials and methods: From January 2022 to December 2023, a total of 150 blood samples were taken from 100 adult dogs in breeding kennels and 50 shepherd dogs in breeding farms in Kerman, Iran. Rose Bengal test (RBT) and Wright tests were used for the primary screening of Brucella abortus (B. abortus) and Brucella melitensis (B. melitensis) species, and conventional IS711-based PCR and real-time polymerase chain reaction (RT-PCR) were performed to determine the Brucella genus and species in all samples.

Findings: In kennel dogs, 34 % (34/100) had a history of breeding disorders, and 30 % (30/100) were RBT-positive. Moreover, B. canis and B. abortus species were detected in kennel dogs. Among farm dogs, 16 % (8/50) had a history of breeding disorders, and 28 % (14/50) were RBT positive. Additionally, B. canis, B. abortus, and B. melitensis species were detected in farm dogs. Feeding with unpasteurized milk was significantly related to a positive RBT in kennel dogs (p = 0.009), and there was a significant correlation between breeding disorders and seropositivity in kennel (p = 0.045) and farm dogs (p = 0.03).

Conclusion: The current study represents a significant advancement in understanding CB in Iran by the first molecular detection of B. canis, revealing B. melitensis and B. abortus as important pathogens in kennel and farm dogs and highlighting the public health significance of disease in Iran.

Crimean-Congo haemorrhagic fever (CCHF) is a viral zoonotic disease endemic to regions of Africa, the Balkans, the Middle East, and Asia, with increasing reports of cases in southern Europe. Human transmission occurs primarily through the bite of infected ticks and by body fluids from infected human. Crimean-Congo haemorrhagic fever virus (CCHFV) affects a broad host range, including both domestic and wild vertebrates. Recent studies have suggested a potential susceptibility of companion animals, posing an additional threat to public health. In the present study, the presence of CCHFV antibodies was evaluated by screening 374 dog and 238 cat serum samples collected from eight Namibian regions using a commercial enzyme-linked immunosorbent assay. Overall, dogs (11.50 %) showed significantly higher odds of seropositivity (OR = 7.60; 95 % CI = 3.02 - 25.51; p-value < 0.001) compared to cats (1.68 %). Most of the positive dogs and all positive cats originated from the Kunene and Hardap regions. No other factors were found to affect seroprevalence. The limited development of farming systems in these regions, combined with the higher roaming activity of dogs, may suggest a greater exposure risk to wild animals or infected ticks. Tick species of the genus Hyalomma are not commonly reported to infest dogs in Namibia, and other tick species may also be involved in transmission. The detection of CCHFV antibodies in dogs and cats in Namibia should be considered by public health authorities as a potential threat, warranting further investigation to identify infection sources and risk factors. While the level and duration of viremia in companion animals, as well as their actual infectivity, remain unknown, efforts should focus on reducing contact between domestic pets, livestock, and wild animals, as well as regular prophylactic tick treatment of pets to prevent or minimise tick infestations.

Spotted fever group Rickettsia (SFGR) infections remain largely under-investigated as causative agents of acute undifferentiated febrile illness (AUFI) in resource-limited settings. Few studies are available on the prevalence of SFGR infections in India, especially in eastern India. In a cross-sectional study conducted in 192 hospitalized adult and paediatric patients with AUFI, the frequency of SFGR using sequential PCR targeting genes encoding citrate synthase (gltA), 17 kDa lipoprotein precursor antigen (17kDa), outer membrane proteins A and B (omp A & omp B) was 6.2% (12/192) including 7.4% (8/108) in adults and 4.7% (4/84) in paediatric patients with AUFI. Phylogenetic analysis of SFGR based on the concatenated sequences of omp A-gltA-17kDa-omp B showed that the patients' isolates obtained in the study clustered with Rickettsia conorii str. Malish 7 (AE006914.1). The SFGR cases described here, to the best of our knowledge, are the first human cases diagnosed in Odisha, eastern coastal India that were laboratory-confirmed by molecular detection and sequencing. The findings of this study will be beneficial for designing systematic future studies covering more geographical locations for continued surveillance of SFGR human infections along with vector surveillance.

Nymphal and larval Amblyomma cordiferum ticks, a relatively rare species, were collected from the Malaysian house rat (Rattus rattus diardii) in Peninsular Malaysia. Redescription and molecular analysis of nymphs and larvae, based on the 12S rRNA, 16S rRNA, and COI genes, revealed divergence from A. cordiferum in Taiwan, suggesting that the Taiwanese tick specimens may represent a different taxon. Molecular analysis of the pathogens in these specimens revealed three sequences of Rickettsia closely related or identical to Rickettsia raoultii (99.71-100%), two sequences of relapsing fever Borrelia identical to Borrelia theileri, and four sequences of Bartonella identical to Bartonella phoceensis. This study also identifies a new host record for A. cordiferum in R. r. diardii and reports the first detection of Rickettsia, Borrelia, and Bartonella in this tick species.

Leishmaniasis is a neglected infectious disease that affects millions of people worldwide. Visceral leishmaniasis (VL) caused by Leishmania infantum and cutaneous leishmaniasis (CL) caused by L. major/ L. tropica are the main clinical forms of this disease, which are life-threatening if not diagnosed and treated properly. Considering the problems in sampling and laboratory diagnosis of leishmaniasis, new molecular markers such as circular RNAs (circRNAs) are needed. circRNAs, a novel class of RNAs, have been one of the most promising targets for the diagnosis and prognosis of diseases. Although the therapeutic and diagnostic role of circRNAs in many diseases and some parasitic diseases are known, not much research has been done in the field of leishmaniasis. We determined the gene expressions of circRNAs in human leukemia monocytic (THP-1) cells after infection with Leishmania. For this, the human cell line THP-1 was differentiated into macrophages by Phorbol 12-myristate 13-acetate (PMA) treatment. Differentiated THP-1 cells were infected with L. infantum and L. tropica promastigotes. After 24 hours, expression levels of circRNAs were determined by RT-qPCR technique. Also, the microRNAs associated with differentially expressed circRNAs were investigated. Then, the molecular pathways associated with expressed circRNAs were obtained by GO and Reactome. The results showed that five circRNAs were differentially expressed in THP1 macrophages infected with L. infantum and L. tropica. These findings suggest that some circRNAs may be potential biomarkers for diagnosis in Leishmania-infected patients. The enrichment analysis revealed that differentially expressed circRNAs are mainly involved in the regulation of protein stability, RNA catabolic process, and P53/PTK6 signaling mechanism. This is the first study to report an overview of Leishmania-induced circRNAs, which can be potential biomarker candidate for diagnosis especially at species level. Notably, expression of some circRNAs in supernatant of Leishmania infected macrophages suggests that these genes are available in body fluids, therefore, can easily be accessed from the patient without invasive methods especially during treatment monitoring.

A new species of Henneguya Thélohan, 1892 (Myxosporea: Bivalvulida: Myxobolidae) infecting the internal region of the stomach of the Peruvian morwong Chirodactylus variegatus (Valenciennes, 1833) (Centrarchiformes: Latridae), an economically important fish in Peruvian artisanal fishery, is described. Morphologically, Henneguya chirodactyli n. sp. differs from all its congeners due to the combination of myxospore dimensions, polar filament coil count, and an external envelope in the spore body. Phylogenetic analysis based on 18S rRNA gene sequences places this new species as sister to H. lagunensis de Azevedo, Negrelli, de Oliveira, Abdallah, Camara, Matos and Vieira, 2021. Furthermore, this species is located in a clade composed of 12 species of Henneguya and one of Myxobolus Bütschli, 1882, all of which infect marine fish. We emphasize that this is the first study performed with an integrative approach, including morphological (external), scanning electron microscopy (SEM) and molecular descriptions, of a Henneguya species from a Peruvian marine environment.

Cryptosporidiosis has been identified as one of the leading causes of diarrhea and diarrhea-associated deaths in young children in sub-Saharan Africa. In Cape Verde, available data on human infections caused by Cryptosporidium spp. are limited. The aim of the present study was to analyze the molecular epidemiology of Cryptosporidium spp. in Cape Verde. Stool samples were obtained from patients on the Santiago and Sal islands (Cape Verde); 10/105 (9.5 % CI: 4.7; 16.8) from the Santiago Island and 4/85 (4.7 % CI: 1.3; 11.6) from the Sal Island presented Cryptosporidium sp., and were analyzed by nested-PCR of the SSU rRNA gene and nested-PCR of the 60 kDa glycoprotein gene for subtyping. Two species, Cryptosporidium hominis and Cryptosporidium felis, were identified. In Santiago Island, only C. hominis was detected, while both species were found in Sal Island. Cryptosporidium hominis IfA 14G1R5 subtype was identified in children from Santiago and Sal. Although the consumption of non-bottled water is a risk factor for infection by Cryptosporidium spp. on Santiago Island, none of the factors analysed (age, gender, clinical symptoms, source of drinking water, presence of animals at home, attending kindergarten or school, and having a bathroom at home) were significantly related to the presence of Cryptosporidium spp. in Sal Island. Cryptosporidium hominis is the most commonly identified species associated with cryptosporidiosis in the studied population, indicating a predominance of anthroponotic transmission. This study provides the first data on C. hominis subtyping in Cape Verde and the first report of C. felis in humans from this region, demonstrating the possibility of zoonotic transmission. The obtained results highlight the need for further molecular and epidemiological studies of Cryptosporidium spp. infections in human and animals from Cape Verde, in order to investigate the transmission dynamics of cryptosporidiosis and develop effective control strategies to prevent the spread of the disease.

Metabolic dysfunction-associated steatotic liver disease (MASLD) and opisthorchiasis, caused by Opisthorchis viverrini (O. viverrini) infection, frequently co-exist in Northeast Thailand. However, the underlying pathophysiology remains unknown. We aimed to investigate the effect of a high-fat/high-fructose (HFF) diet combined with O. viverrini infection on MASLD. Four groups each of ten male golden hamsters were established: normal controls (NC), O. viverrini-infected (OV), HFF-fed, and HFF-fed plus O. viverrini infection (HFF+OV). After four months of treatment, histopathological study indicated substantial hepatic damage in groups given the HFF diet. In particular, the HFF+OV group demonstrated marked lipid-droplet accumulation, hepatocyte ballooning, inflammatory-cell clustering, and widespread fibrosis. Biochemical tests indicated that the HFF+OV group had the highest concentrations of alanine aminotransferase and triglycerides, but cholesterol and low-density lipoprotein levels had increased in both HFF groups. Increased expression of Tgf-β1 and α-SMA, indicative of greater fibrosis, was demonstrated by picrosirius-red staining in the HFF+OV group. There was a significant increase in levels of inflammatory markers (HMGB-1, p65, and F4/80) and expression of genes related to the synthesis of fatty acids and glucose. FTIR microspectroscopy revealed distinct changes in fatty acids and proteins, associated with the more pronounced histopathology and impaired liver function in the HFF+OV group. The findings indicate that the interplay of a HFF diet and O. viverrini infection aggravates the progression of MASLD by augmenting liver damage, inflammation, fibrogenesis, and metabolic dysfunction. This study highlights the significance of incorporating both nutritional and infection factors into the management of liver disorders, especially in areas where opisthorchiasis is common.