Acta tropica最新文献

The biodiversity of freshwater fishes is extensive in Mexico; however, knowledge of their associated myxozoan parasites is limited. This study aimed to recognize myxozoan parasites in the endemic fish Mayaheros urophthalmus. Two new species, Myxobolusmayarum n. sp. and Kudoamayarum n. sp. were described from M. urophthalmus collected in the Celestún Coastal Lagoon and Baldiosera Freshwater Spring from the Yucatán Peninsula. Myxobolusmayarum n. sp. was found in 100% of the examined fish, infecting the gills, kidney, pectoral fins, and spleen. The spores were round, 11.34 ± 0.67 μm length, 10.03 ± 0.44 μm width, and 7.22 ± 0.45 μm thickness. The polar capsules were pyriform and equal in size, 3.85 ± 0.29 μm length and 2.27 ± 0.20 μm width. The polar tubule 30.71 ± 2.10 μm long and coiled 5-6 times. Kudoamayarum n. sp. was found in 30% of fish, infecting the heart, oesophagus, and stomach. The spores were subspherical, 5.40 ± 0.40 μm length and 5.76 ± 0.37 μm width. The polar capsules were ellipsoidal and equal in size, 1.90 ± 0.27 μm length and 1.46 ± 0.20 μm width. The phylogenetic analyses based on the small and large subunits ribosomal DNA (18S rDNA and 28S rDNA) sequences demonstrated that these two species are distinct from other published myxozoans, providing evidence to support the description of two new species. This study constitutes the first record of myxozoans from the Yucatán Peninsula, contributing to increase the knowledge about the biodiversity of myxozoans in neotropical regions.

Vector-borne diseases pose significant threats to both human and animal health, including wildlife, particularly in vulnerable island ecosystems like the Galapagos Islands. This study examines the mosquito community composition around domestic dogs and Galapagos sea lion rookeries across four islands: San Cristobal, Isabela, Santa Cruz, and Floreana. Using BG-Sentinel traps, a total of 292 mosquitoes were collected, identifying three species: Culex quinquefasciatus, Aedes aegypti, and A. taeniorhynchus. Culex quinquefasciatus was the most abundant, with diverse feeding patterns identified through blood meal analysis, revealing host ranges that included domestic chicken, domestic dogs, and sea lions. The presence of Dirofilaria immitis was confirmed in C. quinquefasciatus individuals, indicating a potential risk for heartworm transmission to dogs and to the endangered Galapagos sea lions. Continued surveillance and targeted control measures are crucial for reducing zoonotic disease risks in this fragile ecosystem, emphasizing the need for further research to inform human and animal health prevention strategies.

Mansonia dives is recognized as a vector for brugian filariasis in Thailand. A recent study analyzing the cytochrome c oxidase subunit I (COI) gene revealed two distinct clades within the Ma. dives population in Thailand. This study aimed to examine the genetic diversity and structure of Ma. dives using the COI gene and the internal transcribed spacer 2 (ITS2) region to determine the presence of distinct species or genetically divergent populations. We analyzed 60 COI and 60 ITS2 sequences from Ma. dives populations in Narathiwat, Ranong, Tak, and Trat. The results showed a nucleotide diversity of 0.019 and a haplotype diversity of 0.979 for the COI gene, while the ITS2 region displayed a nucleotide diversity of 0.005 and a haplotype diversity of 0.545. Phylogenetic and haplotype network analyses of the COI gene identified two genetic lineages: one confined to Trat and another encompassing the other sites. However, species delimitation methods suggested that these genetic differences were insufficient to classify the lineages as distinct species. In contrast, the ITS2 analysis indicated a uniform genetic pattern across all populations. We conducted neutrality tests and mismatch distribution to examine the demographic history. For the COI gene, Tajima's D was slightly positive and non-significant (0.014), while Fu's Fs was negative (-9.750), indicating a potential expansion phase. Conversely, for the ITS2 region, Tajima's D and Fu's Fs were positive and non-significant, suggesting that the population might be in equilibrium or undergoing contraction. Moreover, the mismatch distribution analysis for the ITS2 region was inconclusive. The apparent discrepancies between these markers indicate the presence of genetically divergent populations, rather than distinct species.

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.

This study characterizes the Aedes aegypti population from Fernando de Noronha Island, Pernambuco, Brazil, prior to implementing the Sterile Insect Technique (SIT). The main objective was to assess changes in glutathione S-transferase (GST) enzyme activity, previously linked to cypermethrin resistance in this population, in 2010. GST activity was measured in both male and female mosquitoes, masse produced in lab, after exposure to ionizing radiation. The populational evaluation after six years showed a complete susceptibility to cypermethrin, deltamethrin and lambda-cyhalothrin, although GST activity remained altered, increasing furthermore following irradiation (50 % higher in irradiated males and 31 % higher in irradiated females compared to non-irradiated controls). This stress response to gamma radiation suggesting implications for the effectiveness and viability of sterile males, particularly when SIT is combined with chemical insecticides. These findings enhance our understanding of radiation's impact on metabolic responses of the sterile males and provide valuable insights for refining integrated control strategies in vector management programs.

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.

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.