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Author(s):  
Malthe Hvas ◽  
Samantha Bui

Parasites are widespread in nature where they affect energy budgets of hosts, and depending on the imposed pathogenic severity, this may reduce host fitness. However, the energetic costs of parasite infections are rarely quantified. In this study, we measured metabolic rates in recently seawater adapted Atlantic salmon (Salmo salar) infected with the ectoparasitic copepod Lepeophtheirus salmonis and used an aerobic scope framework to assess the potential ecological impact of this parasite-host interaction. The early chalimus stages of L. salmonis did not affect either standard or maximum metabolic rates. However, the later mobile pre-adult stages caused an increase in both standard and maximum metabolic rate yielding a preserved aerobic scope. Notably, standard metabolic rates were elevated by 26%, presumably caused by increased osmoregulatory burdens and costs of mobilizing immune responses. The positive impact on maximum metabolic rates was unexpected and suggests that fish are able to transiently overcompensate energy production to endure the burden of parasites and thus allow for continuation of normal activities. However, infected fish are known to suffer reduced growth, and this suggests that a trade-off exists in acquisition and assimilation of resources despite of an uncompromised aerobic scope. As such, when assessing impacts of environmental or biotic factors, we suggest that elevated routine costs may be a stronger predictor of reduced fitness than the available aerobic scope. Furthermore, studying effects on parasitized fish in an ecophysiological context deserves more attention, especially considering interacting effects of other stressors in the Anthropocene.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yibin Yang ◽  
Xia Zhu ◽  
Haixin Zhang ◽  
Yuhua Chen ◽  
Yi Song ◽  
...  

Host-pathogen intectarions are complex, involving large dynamic changes in gene expression through the process of infection. These interactions are essential for understanding anti-infective immunity as well as pathogenesis. In this study, the host-pathogen interaction was analyzed using a model of acute infection where channel catfish were infected with Yersinia ruckeri. The infected fish showed signs of body surface hyperemia as well as hyperemia and swelling in the trunk kidney. Double RNA sequencing was performed on trunk kidneys extracted from infected channel catfish and transcriptome data was compared with data from uninfected trunk kidneys. Results revealed that the host-pathogen interaction was dynamically regulated and that the host-pathogen transcriptome fluctuated during infection. More specifically, these data revealed that the expression levels of immune genes involved in Cytokine-cytokine receptor interactions, the NF-kappa B signaling pathway, the JAK-STAT signaling pathway, Toll-like receptor signaling and other immune-related pathways were significantly upregulated. Y. ruckeri mainly promote pathogenesis through the flagellum gene fliC in channel catfish. The weighted gene co-expression network analysis (WGCNA) R package was used to reveal that the infection of catfish is closely related to metabolic pathways. This study contributes to the understanding of the host-pathogen interaction between channel catfish and Y. ruckeri, more specifically how catfish respond to infection through a transcriptional perspective and how this infection leads to enteric red mouth disease (ERM) in these fish.


2021 ◽  
Vol 8 ◽  
Author(s):  
Nadia Gabr Ali ◽  
Asmaa Mahmoud El-Nokrashy ◽  
Mofeed Yousef Gouda ◽  
Ibrahim Mohamed Aboyadak

The present work aimed to investigate the causes of summer mortality syndrome affecting cultured European seabass (Dicentrarchus labrax) by examining physiochemical farm water characteristics, isolation, and identification of recovered bacterial pathogens from diseased fish studying the effect of water temperature on stress biomarkers and disease severity. Studied water parameters were normal except ammonia and dissolved oxygen was higher and lower than the standard value. Sixty-two bacterial isolates were recovered from moribund fish and identified as 31 Vibrio fluvialis, 23 Pseudomonas aeruginosa and 8 Staphylococcus aureus isolates. The calculated LD50 of V. fluvialis, P. aeruginosa and S. aureus for D. labrax fingerlings were 4.67 × 107, 2.37 × 106 and 1.38 × 107, respectively. There was a direct correlation between water temperature and mortality rate of fish challenged with V. fluvialis as the mortality rate was 44.44, 50, 66.66, and 83.33% for fish maintained at 27, 30, 33, and 36°C. Plasma cortisol, superoxide dismutase, catalase and malondialdehyde significantly increased when the water temperature exceeded 30°C. The experimentally infected fish showed similar clinical signs and postmortem lesions of naturally diseased fish with no boundary between different pathogens. Antibiogram test indicated that florfenicol was the most effective antibiotic against all the recovered bacterial isolates while all isolates resisted sulfamethoxazole-trimethoprim. Massive degenerative changes observed in the hepatopancreas, posterior kidney and gill tissues of experimentally infected fish.


2021 ◽  
Vol 877 (1) ◽  
pp. 012011
Author(s):  
H M Jarallah

Abstract Fresh water fishes infected with different species of genus Trypanosoma parasite that is similar to that same genus in blood of mammals. Trypanosomiasis or sleeping sickness disease that causes by protozoa flagellate parasites which live inside cell called Trypanosoma. Fish parasites play an important role in regulating the population of their hosts. This study was implemented to verify the infection with Trypanosoma sp. report the cellular intervening through inflammatory response in blood smears of infected fishes. A total of 190 fishes of three species Carasobarbus luteus, Aspius vorax and Liza abu were collected from Al-Hamare and Al-Chibayish marsh south of Iraq. The flagellate parasite Trypanosoma sp. observed in blood of Carasobarbus luteus 41.42% and Aspius vorax 12.28% fishes, while no infection was recorded with Trypanosoma sp. in Liza abu fishes. Prevalence and mean intensity of infection were calculated. The different counts and various types of inflammatory cells were monitored, there are increased in lymphocytes in the infected fishes. Statistically, there are significant differences (p<0.05) among species of infected fish with Trypanosoma sp.


2021 ◽  
Vol 934 (1) ◽  
pp. 012006
Author(s):  
M Riauwaty ◽  
Windarti

Abstract Curcumin is an antibiotic agent extracted from Curcuma longa. To understand the effectiveness of curcumin in curing the gill of Clarias batrachus infected with Aeromonas hydrophila, a study was conducted from August to November 2020. There were 3 treatments applied, namely turmeric enriched pellets 0.7g/kg (P1); 0.9g/kg (P2) and 1.1g/kg (P3). Prior to the treatment, the fish was infected with A. hydrophila (0.1 m of A. hydrophila culture, 1.0x108cells/ml). The infected fish was kept for 6 days until the clinical signs of MAS disease occurred. By the 7th day, the fish was feed with turmeric enriched pellets. For negative control (Cn) the fish was not infected with A. hydrophila nor treated with turmeric, while the positive control (Cp) was infected, but no turmeric treatment. The fish was reared for 30 days and by the end of the experiment, the gill was removed and processed for histological study (5L sliced and HE stained). Result indicated that the gill of the negative control fish was normal, while that of the positive control shown abnormalities such as hemorrhages, necrotic cells, fused lamellae and enlarged cartilaginous cells. The turmeric treated fish shown less damage in the gill. The best results were obtained in C3, as the gill structure was almost normal with slightly hemorrhage. In the C1 and C2 treated fishes, the gill shown light abnormality such as fused lamella and hemorrhage. Data obtained shown that the consumption of turmeric enriched pellet was effective to cure the A. hydrophyla infected gill.


2021 ◽  
Vol 4 (4) ◽  
pp. 99-108
Author(s):  
Ngodhe S.O. ◽  
Kerich E. ◽  
Kipkorir K.

The general objective of this study was to assess the effects of parasitism on the production and productivity of caged Oreochromis niloticus in Winam Gulf of L. Victoria. With the need to increase food production through fish products amid overfishing and pollution stress in the lake, cage farming is seen to have the potential to bridge the fish supply and demand gap continues to widen. Cage culture is a new technology in the offing that needs to be explored to justify its potential. Fish parasites are always a threat in an enclosed culture system and because of this, it is necessary to assess their effects on fish condition factors before recommendation. It is because of this reason that a total of 480 caged Oreochromis niloticus were purchased and examined for parasites using the recommended procedures for parasitological analysis. The class Trematoda which included seven taxa were found to be the most common and prevalent parasites in cages of the Winam Gulf. This was attributed to the presence of piscivorous birds which are definitive hosts seen more often around the culture systems and also overstocking observed and reported during the study period which increases the spread and transmission of parasites from one fish to another. Despite the prevalence, infestation did not affect the fish condition factor in all the study areas as the majority of infected fish recorded between good and excellent body condition factors. This was due to low mean intensities recorded and a shorter period of exposure to parasitic infestation as most farmers were barely 3 years into the system. In conclusion, for the government to explore the blue economy and achieve the Vision 2030 and SDGs on food security and poverty reduction by 2030, efforts to promote commercial cage culture enterprises in the Winam Gulf must be bolstered, provided that cages are located in deep waters with low concentrations in specific areas and low stocking densities to avoid compromising the environment.


2021 ◽  
Vol 43 ◽  
pp. e57163
Author(s):  
Lucena Rocha Virgilio ◽  
Fabricia da Silva Lima ◽  
Luciano Negreiros ◽  
Ricardo Massato Takemoto ◽  
Luís Marcelo Aranha Camargo ◽  
...  

Prochilodus nigricans is extensively exploited in fishing and aquaculture activities in the Brazilian Amazon, it is the definitive host for Neoechinorhynchus curemai Noronha, 1973. Thus, the present study aimed to evaluate the occurrence of N. curemai in P. nigricans and the parasite-host relationship in three rivers (Juruá, Crôa and Môa) in the municipality of Cruzeiro do Sul, state of Acre, Brazil. Fish were caught, weighed, measured, and subjected to necropsy, and the gastrointestinal tract and viscera were analyzed. A total of 178 specimens of N. curemai were found in 61 infected fish, with the (p= 58.62%). The prevalence, mean intensity, and mean abundance were higher in hosts from the Môa River, and lower from the Juruá River. Regarding the length-weight relationship, the b-value did not differ statistically from three (b=3) for fish species in the three locations, nor in parasitized and non-parasitized species. In addition, growth was considered isometric, and in the case of the relative condition factor, there was no difference in fish hosts between the three rivers. The correlation between parasite intensity, condition factor, length, and weight of P. nigricans was not significant. Thus, this parasite infestation varied between the habitats. However, this did not influence the growth and development of the hosts.


Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1302
Author(s):  
Sara Buzo-Domínguez ◽  
Manuel Morales-Yuste ◽  
Ana María Domingo-Hernández ◽  
Rocío Benítez ◽  
Francisco Javier Adroher

The presence of third stage larvae (L3) of Anisakis spp. in wedge sole, Dicologlossa cuneata (Moreau, 1881), purchased in fishmarkets in the city of Granada (Andalusia, southern Spain) was assessed. The wedge sole were caught in two FAO zones: area 27.IXa NE Atlantic (SW Spain coast) and area 34.1.11 CE Atlantic (NW Morocco coast). Only Anisakis larvae, type I, were detected in the largest fish (>20 cm) from the CE Atlantic. These were molecularly identified as A. simplex s.s. The prevalence (P) of Anisakis in this area was 12.5% and the mean intensity (MI) was 1. The presence of Hysterothylacium spp. larvae was also detected in the fish from both areas, with the prevalence being approximately double in the CE Atlantic area (12.5 vs. 5.7). A comparison between the Anisakis-infected and non-infected fish from this area showed that the former were significantly longer than the latter (p < 0.01). These results show that Anisakis parasitization of wedge sole sold in the markets of the city of Granada is of low prevalence and intensity (P = 4.5, MI = 1), especially in those from area 27.IXa (P = 0), indicating that the risk of human infection is low, particularly as this fish is traditionally prepared by deep-frying in oil in Andalusia (southern Spain).


2021 ◽  
Vol 75 (11) ◽  
Author(s):  
Nicolle Demandt ◽  
David Bierbach ◽  
Ralf H. J. M. Kurvers ◽  
Jens Krause ◽  
Joachim Kurtz ◽  
...  

Abstract A key benefit of sociality is a reduction in predation risk. Cohesive group behaviour and rapid collective decision making are essential for reducing predation risk in groups. Parasite infection might reduce an individuals’ grouping behaviours and thereby change the behaviour of the group as a whole. To investigate the relationship between parasite infection and grouping behaviours, we studied groups of three-spined sticklebacks, Gasterosteus aculeatus, varying the number of individuals experimentally infected with the cestode Schistocephalus solidus. We studied groups of six sticklebacks containing 0, 2, 3, 4 or 6 infected individuals before and after a simulated bird attack. We predicted that infected individuals would have reduced shoaling and swimming speed and that the presence of infected individuals within a group would reduce group cohesion and speed. Uninfected fish increased shoaling and reduced swimming speed more than infected fish after the bird attack. In groups containing both infected and uninfected fish, the group behaviours were dominated by the more frequent character (uninfected versus infected). Interestingly, groups with equal numbers of uninfected and infected fish showed the least shoaling and had the lowest swimming speeds, suggesting that these groups failed to generate a majority and therefore displayed signs of indecisiveness by reducing their swimming speed the most. Our results provide evidence for a negative effect of infection on a group’s shoaling behaviour, thereby potentially deteriorating collective decision making. The presence of infected individuals might thus have far-reaching consequences in natural populations under predation risk. Significance statement Parasite-infected individuals often show deviating group behaviours. This might reduce the anti-predator benefits of group living. However, it is unknown whether such deviations in group behaviour might influence the shoaling behaviour of uninfected group members and thereby the behaviour of the group as a whole. By experimentally infecting sticklebacks and investigating groups varying in infection rates, we show that infected sticklebacks differ in their shoaling behaviours from uninfected sticklebacks. Additionally, the presence of infected sticklebacks within the group affected the behaviour of uninfected shoal members. We show that shoals of infected fish are less cohesive and move slower compared to shoals of uninfected fish. Furthermore, we show that the infection rate of the shoal is crucial for how the group behaves.


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