Histopathology of the mangrove land crab Ucides cordatus (Ocypodidae) affected by lethargic crab disease (original) (raw)
Related papers
Lethargic crab disease: multidisciplinary evidence supports a mycotic etiology
Memórias do Instituto Oswaldo Cruz, 2005
Although lethargic crab disease (LCD) is causing massive mortalities in populations of the mangrove crab Ucides cordatus of Northeastern Brazil, the identity of its etiological agent was hitherto unknown. In this study we provide robust evidence suggesting that LCD is caused by an anamorph Ascomycota (Fungi). We examined specimens of U. cordatus collected from stocks affected by LCD. Histological and TEM methods detected the presence of hyphae, conidia, and condiophores in several host tissues. Moreover, the abundance of fungal stages is negatively associated with crab health. Finally, DNA was isolated from the fungus and a region of its 18S ribosomal gene was sequenced. Phylogenetic analyses not only confirm the diagnosis of the LCD fungus in crab tissues as an ascomycete, but also suggest a close relationship with members of the subphylum Pezizomycotina.
Lethargic Crab Disease: Now You See, Now You Don’t
Emerging and Epizootic Fungal Infections in Animals, 2018
An infectious disease has caused high mortalities in the Brazilian mangrove-land crab, Ucides cordatus. The lethargic crab disease spread northward and southward in waves from Pernambuco State in Brazil. Primary causative agent was the black yeast Exophiala cancerae, with Fonsecaea brasiliensis as a secondary, opportunistic invader. The reasons for coming and going of the disease may be of intrinsic as well as of environmental nature.
Fulfilling Koch’s postulates confirms the mycotic origin of Lethargic Crab Disease
Antonie van Leeuwenhoek, 2011
In the northeast region of the Brazilian coast, a disease has been causing massive mortalities of populations of the mangrove land crab, Ucides cordatus (L.) since 1997. The clinical signs of this disease, which include lethargy and ataxia, led to the disease being termed Lethargic Crab Disease (LCD). Evidence from a variety of sources indicates that there is an association between LCD and a new species of black yeast, Exophiala cancerae de Hoog, Vicente, Najafzadeh, Badali, Seyedmousavi & Boeger. This study tests this putative correlation through in vivo experiments. Disease-free specimens of U. cordatus were experimentally infected with Exophiala cancerae (strain CBS 120420) isolate. During the 30-day experimental period, only a single death was observed within the control crabs. However, at the end of this period, crabs that were inoculated once or three-times with mycelial elements and hyphae of E. cancerae had a 60% and 50% mortality rates, respectively (n = 6 and n = 5). These results support that the fungal agent is pathogenic and is the causative agent of LCD. Species-specific molecular markers confirm the presence of E. cancerae (strain CBS 120420) in recovered colonies and tissue samples from the infected animals. The experimentally infected crabs manifested signs (lethargy, ataxia and tetany) that were consistent to LCD-affected animals in the environment. These results fulfil Koch's postulates and the hypothesis that the tested strain of Exophiala cancerae is a causative agent of LCD is accepted.
Food Control, 2012
One of the most typical seafood dishes in the Brazilian coastal areas is the cooked mangrove-land crab, Ucides cordatus (L.). Mortality events of U. cordatus were reported from a large extension for over 15 years, especially in the Northeast region. These mortalities are known to be triggered by an epizooty known as Lethargic Crab Disease, for which the putative etiological agent is a new species of black yeast, Exophiala cancerae De Hoog, Vicente, Najafzadeh, Harrak, Seyedmousavi, & Boeger. Although there is no compelling evidence that this fungus may represent a zoonosis, there is great public concern regarding consumption of crabs from affected regions. Thus, this study evaluates the efficiency of cooking procedures on the inactivation of the etiologic agent. The variation of the internal temperature of crabs and tests of the activity of E. cancerae to temperature under simulated cooking condition were determined and the results were analyzed combined. The results indicate that crab's core body attains the boiling water temperature about an average of 14 min after exposition. Furthermore, short intervals of exposure (30 s) to such boiling temperatures were sufficient to warrant inactivation of E. cancerae. Thus, the traditional mode of preparation of the mangrove-land crab is sufficient to inactivate the pathologic agent and the consumption of sick or carrier animals should not represent a potential public health risk.
Emerging Diseases and Epizootics in Crabs Under Cultivation
Frontiers in Marine Science
While most crab production for human consumption worldwide comes from capture fisheries, there is increasing production of selected species using aquaculture-based methods. This is both for the purpose of stock replacement and direct yield for human consumption. Disease has limited the ability to produce larval crabs in commercial hatcheries and this together with suitable feeds, are major hurdles in the sustainable development of cultivation methods. Juvenile and adult crabs are also subject to a range of diseases that can cause severe economic loss. Emerging pathogens/parasites are of major importance to crab aquaculture as they can cause high levels of mortality and are difficult to control. Diseases caused by viruses and bacteria receive considerable attention but the dinoflagellate parasites,Hematodiniumspp., also warrant concern because of their wide host range and lack of control methods to limit their spread. This concise review examines the emerging diseases in several crab...
Some histopathological alteration of the infected blue crab Portunus pelagicus with parasites
Egyptian journal of aquatic biology and fisheries, 2020
The blue crabs are valuable sea food of great demand, both in domestic markets and in the export industry. They are intertidal species with low migration that can be found throughout the year (Robert et al., 2014 ; Zairon et al., 2015). P. pelagicus inhabits the Middle eastern coast of Mediterranean sea, Red sea and Suez Canal (Mehanna, 2005 & Mehanna and El-Aiatt, 2011). It lives in sandy mud habitat until shallow water down to 50 m (Fazrul et al., 2015). Vogan et al. (2001) stated that crabs have been known to have parasites that caused histopathological alterations to their organs and tissues. Histology is the standard method for the examination of crab tissues to identify the presence of parasites and their related pathologies (Bojko et al., 2013). ARTICLE INFO ABSTRACT Article History: Received: June 6, 2020 Accepted: July 3, 2020 Online: July 7, 2020 _______________
Mycosis Is a Disease State Encountered Rarely in Shore Crabs, Carcinus maenas
Pathogens
There is a paucity of knowledge regarding the diversity and impact(s) of disease-causing fungi in marine animals, especially shellfish. In efforts to address this knowledge gap for the shore crab Carcinus maenas, a year-long disease screen was carried out across two sites in Swansea Bay (Wales, UK) with a view to characterising putative fungal infections. Crabs were sampled between November 2017 and October 2018, and screened systematically for disease signatures using haemolymph (blood) preparations, targeted PCR and tissue histopathology. Strikingly, mycosis was confirmed in ~0.4% of total crabs tested (n = 1191) and restricted to one location only (Mumbles Pier). Clinical infections were observed in four out of four infected crabs. In these animals, the gills and hepatopancreas were congested with fungal morphotypes. In addition, some evidence indicates haemocyte (immune cell) reactivity toward the fungi. Phylogenetic placement of the partial internal transcribed spacer (ITS1) ge...
Green algal infection of American horseshoe crab (Limulus polyphemus) exoskeletal structures
Journal of Invertebrate Pathology, 2012
Degenerative lesions in the dorsum of the horseshoe crab (Limulus polyphemus) exoskeleton, eyes, arthrodial membrane, and base of the telson were documented in a population of wild caught laboratory animals. The disease can lead to loss of tissue structure and function, deformed shells, abnormal molting, loss of ocular structures, erosion of interskeletal membranes, and cardiac hemorrhage. Microscopy, histopathology, and in vitro culture confirmed the causative agent to be a green algae of the family Ulvaceae. Further research may explain how green algae overcome horseshoe crab innate immunity leading to external and internal damage.