The impact of co-infections on fish: a review

International audienceAbstractCo-infections are very common in nature and occur when hosts are infected by two or more different pathogens either by simultaneous or secondary infections so that two or more infectious agents are active together in the same host. Co-infections have a fundamental effect and can alter the course and the severity of different fish diseases. However, co-infection effect has still received limited scrutiny in aquatic animals like fish and available data on this subject is still scarce. The susceptibility of fish to different pathogens could be changed during mixed infections causing the appearance of sudden fish outbreaks. In this review, we focus on the synergistic and antagonistic interactions occurring during co-infections by homologous or heterologous pathogens. We present a concise summary about the present knowledge regarding co-infections in fish. More research is needed to better understand the immune response of fish during mixed infections as these could have an important impact on the development of new strategies for disease control programs and vaccination in fish

Within-farm spread of infectious salmon anemia virus (ISAV) in Atlantic salmon Salmo salar farms in Chile

Spread of infectious salmon anemia virus (ISAV) at the cage level was quantified using a subset of data from 23 Atlantic salmon Salmo salar farms located in southern Chile. Data collected from official surveillance activities were systematically organized to obtain detailed information on infectious salmon anemia (ISA) outbreaks. Descriptive statistics for outbreak duration, proportion of infected fish, and time to secondary infection were calculated to quantify the magnitude of ISAV incursions. Linear and multiple failure time (MFT) regression models were used to determine factors associated with the cage-level reproduction number (Rc) and hazard rate (HR) for recurrent events, respectively. In addition, the Knox test was used to assess if cage-to-cage transmissions were clustered in space and time. Findings suggest that within farms, ISA outbreaks, on average, lasted 30 wk (median = 26 wk, 95% CI = 24 to 37 wk) and affected 57.3% (95% CI = 47.7 to 67.0%) of susceptible cages. The median time to secondarily diagnosed cages was 23 d. Occurrence of clinical ISAV outbreaks was significantly associated with increased Rc, whereas increased HR was significantly associated with clinical outbreaks and with a large number of fish. Spatio-temporal analysis failed to identify clustering of cage cases, suggesting that within-farm ISAV spread is independent of the spatial location of the cages. Results presented here will help to better understand ISAV transmission, to improve the design of surveillance programs in Chile and other regions in which salmon are intensively farmed, and to examine the economic impact of ISAV and related management strategies on various cost and demand shifting factors

A Latin American survey on demographic aspects of hospitalized, decompensated cirrhotic patients and the resources for their management

Introduction & objectives: Liver cirrhosis is a major cause of mortality worldwide. Adequate diagnosis and treatment of decompensating events requires of both medical skills and updated technical resources. The objectives of this study were to search the demographic profile of hospitalized cirrhotic patients in a group of Latin American hospitals and the availability of expertise/facilities for the diagnosis and therapy of decompensation episodes. Methods: A cross sectional, multicenter survey of hospitalized cirrhotic patients. Results: 377 patients, (62% males; 58 ± 11 years) (BMI > 25, 57%; diabetes 32%) were hospitalized at 65 centers (63 urbans; 57 academically affiliated) in 13 countries on the survey date. Main admission causes were ascites, gastrointestinal bleeding, hepatic encephalopathy and spontaneous bacterial peritonitis/other infections. Most prevalent etiologies were alcohol-related (AR) (40%); non-alcoholic-steatohepatitis (NASH) (23%), hepatitis C virus infection (HCV) (7%) and autoimmune hepatitis (AIH) (6%). The most frequent concurrent etiologies were AR + NASH. Expertise and resources in every analyzed issue were highly available among participating centers, mostly accomplishing valid guidelines. However, availability of these facilities was significantly higher at institutions located in areas with population > 500,000 (n = 45) and in those having a higher complexity level (Gastrointestinal, Liver and Internal Medicine Departments at the same hospital (n = 22). Conclusions: The epidemiological etiologic profile in hospitalized, decompensated cirrhotic patients in Latin America is similar to main contemporary emergent agents worldwide. Medical and technical resources are highly available, mostly at great population urban areas and high complexity medical centers. Main diagnostic and therapeutic approaches accomplish current guidelines recommendations