Infectivity, transmission and 16S rRNA sequencing of a rickettsia, Coxiella cheraxi sp. nov., from the freshwater crayfish Cherax quadricarinatus

Tan, Che-Kim; Owens, Leigh

doi:10.3354/dao041115

Cited by 54 publications

(39 citation statements)

References 21 publications

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“…For example, one form of rickettsiosis in the freshwater crayfish Cherax quadricarinatus is caused by Coxiella cheraxi (Tan & Owens, 2000). Further ultrastructural studies of this disease in Ch.…”

Section: Discussionmentioning

confidence: 99%

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A novel bacterial disease of the European shore crab, Carcinus maenas – molecular pathology and epidemiology

et al. 2007

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A novel bacterial disease of the European shore crab, Carcinus maenas -molecular pathology and epidemiology Several rickettsia-like diseases have been reported in arthropods (insects and crustaceans), some of which result in significant losses of economically important species such as shrimp and crabs. This study reports on the molecular pathology of a recently emerged disease of the European shore crab, Carcinus maenas, termed milky disease -named as a result of the unusual milky appearance of the haemolymph (blood). This disease was more prevalent (.26 %) during summer months when the water temperature in a pilot crab farm was approximately 19 6C. The putative causative agent of the disease was a Gram-negative bacterium that could not be cultured on a range of agar-based growth media. Diseased crabs showed significant reductions in free blood cell numbers and total serum protein. Such animals also displayed raised levels of glucose and ammonium in blood. Ultrastructural and in situ hybridization studies revealed that the causative agent associated with milky disease multiplied in the fixed phagocytes of the hepatopancreas (digestive gland), ultimately to be released into the haemolymph, where the circulating blood cells showed little response to the presence of these agents. Attempts to induce the infection by short-term temperature stress failed, as did transmission experiments where healthy crabs were fed infected tissues from milky disease affected individuals. Sequence analysis of the 16S rRNA gene from the milky disease bacteria indicated that they are a previously undescribed species of a-proteobacteria with little phylogenetic similarity to members of the order Rickettsiales. INTRODUCTIONThere is increasing interest in the likely effect of global climate change on diseases in both wild and cultured organisms (Harvell et al., 1999(Harvell et al., , 2002Lafferty et al., 2004). In particular, aquatic animals are highly sensitive to temperature change and it is widely accepted that elevated temperatures can lead to reduced oxygen tension in the water, higher microbial growth and immunosuppression, resulting in higher prevalence of disease (Le Moullac & Haffner, 2000). For example, brown trout in alpine rivers and streams have been found to show increasing prevalence of proliferative kidney disease caused by the myxozoan parasite Tetracapsuloides bryosalmonae over the last 20 years (Hari et al., 2006). These increased temperatures drive the proliferation of T. bryosalmonae in its intermediate bryozoan host (Tops et al., 2006). Equally at very low water temperatures, some aquatic animals may become immunocompromised as a result of a failure of the immune system to mount an effective immune response to bacterial challenge (Chisholm & Smith, 1994).One potentially important result of climate change will be alterations in the effectiveness of aquaculture as a method of supplementing fish and shellfish for human and animal consumption taken from the wild (Alborali, 2006). Currently, it is thought that at least 15 ...

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Section: Discussionmentioning

confidence: 99%

“…7A inset). Many of the fixed phagocytes contained (Tan, 1998;Tan & Owens, 2000). The numbers at the branch points are the bootstrap values.…”

Section: Transmission Electron Microscopy (Tem)mentioning

confidence: 99%

A novel bacterial disease of the European shore crab, Carcinus maenas – molecular pathology and epidemiology

et al. 2007

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“…Frozen rickettsia tissue for the development of PCR and in situ hybridization assays was obtained from a farm in Madagascar that had sustained daily Peneaus monodon mortalities. The method for purification of the bacteria was adapted from Tan & Owens (2000). Briefly, 12.5 g of cephalothorax tissues with the carapaces removed were homogenized in 0.9% saline and 0.1% Tween 20 (PST) (500 ml ddH 2 O, 4.5 g NaCl, 0.5 ml Tween 20).…”

Section: Methodsmentioning

confidence: 99%

Molecular detection methods developed for a systemic rickettsia-like bacterium (RLB) in Penaeus monodon (Decapoda: Crustacea)

Nunan¹,

Poulos²,

Redman³

et al. 2003

Dis. Aquat. Org.

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Molecular detection methods were developed to aid in the diagnosis of a rickettsia-like bacterium (RLB) which caused severe mortalities of farm-raised Penaeus monodon in Madagascar. Using primers derived from the 16S rRNA gene of bacteria, a PCR assay was optimized to amplify this region of the genome of the RLB, using extracted DNA from infected P. monodon tissue as the template. The resulting amplified PCR product was sequenced and 2 novel primers were selected from the variable region of the gene. These primers amplified a 532 bp fragment of DNA originating from the rickettsia-infected samples. The PCR assay was optimized and tested on DNA extracted from specific pathogen-free (SPF) P. vannamei tissue and several other strains of bacteria. The PCR assay with the rickettsia-specific primers was specific for this RLB and did not amplify the other DNA samples tested. The 532 bp PCR-amplified fragment was labeled with digoxigenin (DIG) for in situ hybridization assays. This probe was tested on SPF, RLB and bacteria-infected shrimp specimens preserved in Davidson's fixative. The probe was specific for both natural and experimental rickettsial infections. Hybridization with this probe required a stringent temperature of 65°C, otherwise cross-reactivity was observed with other types of bacteria. KEY WORDS: Rickettsia · Penaeus monodon · Shrimp · CrustaceaResale or republication not permitted without written consent of the publisher

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“…However, further studies on immunology and molecular biology (Tan & Owens 2000) will be needed to determine its relationship to other RLOs.…”

mentioning

confidence: 99%

Rickettsia-like organism associated with tremor disease and mortality of the Chinese mitten crab Eriocheir sinensis

Wang

Gu²

2002

Dis. Aquat. Org.

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We report the discovery of a rickettsia-like organism (RLO) in cultured freshwater Chinese mitten crab Eriocheir sinensis. The RLO caused tremor disease and was apparently responsible for a mass mortality (30 to 90%) in 2 provinces in southeast China. Moribund crabs were investigated from different districts during outbreaks in 1999 and 2000. With electron microscopy, 3 different pathogens were detected in moribund crabs: a rickettsia-like organism (RLO), virus-like particles (VLP) and a microsporidian-like protozoan (MLP). Based on the high prevalence, infection intensity and cytopathological signs, the RLO was considered to be the probable cause of the high mortality. Both VLP and MLP occurred at low prevalences and were considered secondary infections. The RLO was 0.22 to 0.35 µm in diameter, granular or clavate, bounded by a cell wall and membrane, and possessed no nucleus but a nucleoid was present. When dividing, RLOs occurred in irregular shapes, such as dumbbells, awls, and crescents. The RLOs exhibited a predilection for muscle and connective tissues and were probably transported to various tissues and organs by hemocytes.

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Infectivity, transmission and 16S rRNA sequencing of a rickettsia, Coxiella cheraxi sp. nov., from the freshwater crayfish Cherax quadricarinatus

Cited by 54 publications

References 21 publications

A novel bacterial disease of the European shore crab, Carcinus maenas – molecular pathology and epidemiology

A novel bacterial disease of the European shore crab, Carcinus maenas – molecular pathology and epidemiology

Molecular detection methods developed for a systemic rickettsia-like bacterium (RLB) in Penaeus monodon (Decapoda: Crustacea)

Rickettsia-like organism associated with tremor disease and mortality of the Chinese mitten crab Eriocheir sinensis

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