Parasitologia

Sea lice (Caligus rogercresseyi) are major ectoparasites in Chilean salmon aquaculture, causing economic losses and increasing fish susceptibility to secondary infections. Tenacibaculosis has recently emerged as the second leading cause of mortality in farmed salmon. Understanding whether sea lice may harbor or transmit bacterial pathogens is therefore highly relevant. A sea lice survey was conducted at an Atlantic salmon (Salmo salar) farm in the Los Lagos Region, Chile. Twenty adult parasites (10 ovigerous females and 10 males) were analyzed using an integrated approach combining immunohistochemistry (IHC) with specific antibodies and conventional PCR with appropriate controls. IHC revealed positive signals for Tenacibaculum maritimum in the gastrointestinal tract and cuticle, and for Tenacibacuum dicentrarchi in the cuticle and ovigerous sac of C. rogercresseyi. A specific PCR test confirmed the presence of both pathogens, yielding amplification products of 1088 bp for T. maritimum and 284 bp for T. dicentrarchi. This study provides the first dual evidence, by PCR and IHC, of Tenacibaculum species in C. rogercresseyi. These findings suggest that sea lice may play a role in pathogen dynamics in salmon farming, highlighting the need for further research on their contribution to disease transmission within aquaculture systems.

Monitoring hematological indicators and the dynamics of hemotropic agents in sheep production is essential for diagnosing the animals’ health status under field conditions. The aim of this study was to evaluate the frequency of hemotropic agents and the hematophysiological variability associated with intrinsic and extrinsic factors in sheep from the “Lanero” Foothills (Colombian Orinoquia). One hundred and forty-eight Creole sheep (43 males aged 2 to 36 months and 105 females aged 2 to 48 months) from seven production units were sampled. Blood samples were collected by jugular venipuncture to determine the complete hematological profile and the presence of hemotropic agents using Wright-stained blood smears. Five classification criteria (farm, sex, age, body condition score, and FAMACHA^® scale) were evaluated based on three physiological variables and eight hematological parameters. Sex was the only intrinsic factor with a significant influence (p < 0.05) on hematocrit, hemoglobin, eosinophils, and platelets (p < 0.05), which remained within the reference ranges for the species. Females exhibited higher values for hematocrit (30.5 vs. 28.0%), hemoglobin (10.5 vs. 9.8 g/dL), and eosinophils (0.66 vs. 0.52 × 10⁹/L), while males presented higher platelet values (467.7 vs. 323.6 × 10⁹/L). Anaplasma spp. was the most frequent (52.03%). An interaction (p < 0.05) was observed between the “farm” factor and the frequency of Anaplasma spp. Sex and age were not associated with the frequency of any hemotropic agent. (p > 0.05). Evaluation using FAMACHA^® was consistent with the absence of clinical anemia in the evaluated population. The results demonstrate the remarkable clinical and hematological resilience of the region’s Creole sheep against hemotropic agents, reinforcing a scenario consistent with a state of enzootic stability.

This study assessed the diagnostic reliability of anti-Schistosoma serology in Ghanaian patients with and without concomitant human immunodeficiency virus (HIV) infection. Serological testing was performed on serum samples containing PCR-confirmed Schistosoma spp. DNA using a commercial enzyme-linked immunosorbent assay (ELISA; EUROIMMUN, Lübeck, Germany). Following real-time PCR confirmation of either Schistosoma mansoni or Schistosoma haematobium complex DNA, samples were subjected to anti-Schistosoma IgG and IgM serology in duplicate. Results were qualitatively interpreted as positive, uncertain, or negative; reproducible positive results across test runs were defined as “consistent,” while all other profiles were classified as “inconsistent”. Serological consistency was then correlated with patient demographic and clinical data, including age, gender, HIV status, CD4+ and CD8+ T-lymphocyte counts, CD4+/CD8+ ratios, and HIV viral loads. Of the 41 individuals with PCR-proven schistosomiasis (S. mansoni, n = 36; S. haematobium, n = 5) and no clinical signs of Katayama syndrome, 39 were HIV-positive. Among these 39 coinfected patients, consistently positive serology was recorded in 27 (69.2%) cases for IgG and 31 (79.5%) cases for IgM. Consistent IgG seropositivity was significantly associated with higher CD4+ (293 vs. 58 cells/µL, p = 0.009) and CD8+ (981.5 vs. 306 cells/µL, p = 0.007) T-lymphocyte counts. The association between higher CD4+ cell counts and consistent IgG reactivity remained robust in multivariable analysis (adjusted odds ratio = 2.04 per 100 cells/µL, p = 0.01). A non-significant trend in the same direction was observed for anti-Schistosoma IgM, whereas no other significant associations with epidemiological or medical factors were identified. In conclusion, the state of cellular immunity critically influences the reliability of serological schistosomiasis diagnostics in HIV-positive individuals. For patients with severe cellular immune depletion and suspected schistosomiasis, alternative diagnostic approaches, such as highly sensitive real-time PCR, should be strongly considered.