A case of mistaken identity: a systematic review, meta-analysis, and reinvestigation of hemotropic Mycoplasma spp. infection in Ctenocephalides felis (cat flea)

BACKGROUND

Feline-associated hemotropic Mycoplasma (hemoplasmas) are believed to be transmitted by two primary mechanisms: (1) direct transmission via fighting and (2) vector-borne transmission by the cat flea (Ctenocephalides felis). While the efficiency of transmission by C. felis appears low, most manuscripts focus on the prevalence of hemoplasmas in wild-caught fleas and report either a very low (< 3%) or a high (> 26%) prevalence. Therefore, we aimed to assess the influence of sample processing and PCR methods on C. felis hemoplasma infection prevalence.

METHODS

A systemic review of PubMed articles identified 13 manuscripts (1,531 fleas/flea pools) that met the inclusion criteria (performed PCR for >1 hemoplasma on C. felis collected from cats). Risk of bias was assessed utilizing the ROBINS-E tool. Meta-analysis performed in R of these manuscripts found that not washing samples and a common set of 16S rRNA primers first published in Jensen et al. 2001 were associated with increased hemoplasma prevalence. To evaluate the influence of washing on newly collected fleas, we assessed the hemoplasma status of 20 pools of 5 C. felis each, half of which were washed and half not washed.

RESULTS

Flea washing did not influence the detection of hemoplasma but instead amplified Spiroplasma. To assess non-specific amplification with the Jensen et al. 2001 primers, 67 C. felis samples (34% previously reported hemoplasma infected) were subject to PCR and sequencing. By this method, hemoplasma was detected in only 3% of samples. In the remaining "hemoplasma infected" fleas, PCR amplified Spiroplasma or other bacteria.

CONCLUSIONS

Therefore, we concluded that hemoplasma infection in C. felis is rare, and future flea prevalence studies should sequence all positive amplicons to validate PCR specificity. Further investigation of alternative methods of feline-associated hemoplasma transmission and the ability of C. felis to maintain hemoplasma infection is necessary.

First molecular evidence of bovine hemoplasma species (Mycoplasma spp.) in water buffalo and dairy cattle herds in Cuba

BACKGROUND

Hemotropic mycoplasmas (aka hemoplasmas) are small bacteria which cause infectious anemia in several mammalian species including humans. Information on hemoplasma infections in Cuban bovines remains scarce and no studies applying molecular methods have been performed so far. The aim of the present study was to utilize real-time PCR and sequence analysis to investigate dairy cattle and buffalo from Cuba for the presence of bovine hemoplasma species.

RESULTS

A total of 80 blood samples from 39 buffalo and 41 dairy cattle were investigated for the presence of Mycoplasma wenyonii and "Candidatus Mycoplasma haemobos" using two species-specific real-time TaqMan PCR assays. PCR results revealed overall 53 (66.2%; 95% CI: 55.3-75.7%) positive animals for M. wenyonii and 33 (41.2%; 95% CI: 31.1-52.2%) for "Ca. M. haemobos"; the latter were all co-infections with M. wenyonii. The sample prevalences were similar in cattle and buffalo. Based on the sequence analysis of the nearly full-length 16S rRNA gene from two cattle and two buffalo, the presence of M. wenyonii and "Ca. M. haemobos" was confirmed. Statistical analysis revealed that buffalo and cattle one year of age or older were more frequently infected with M. wenyonii or "Ca. M. haemobos" than younger animals. PCR-positivity was not associated with anemia; however, the infection stage was unknown (acute infection versus chronic carriers).

CONCLUSIONS

The high occurrence of bovine hemoplasma infections in buffalo and dairy cattle may have a significant impact on Cuban livestock production. To the best of our knowledge, this is the first molecular evidence of bovine hemoplasma species infection in dairy cattle and buffalo from Cuba and the Caribbean.

High diversity of blood-associated parasites and bacteria in European wild cats in Bosnia and Herzegovina: A molecular study

Wild felids may play a significant role in the transmission of various pathogens to domestic cats, in particular, but also to other animals and humans. However, since data on the occurrence of blood-borne organisms in European wild cats (Felis silvestris silvestris) are scarce, the present study aimed to provide an insight into the genetic diversity of the agents carried by this sylvatic species in Bosnia and Herzegovina and to elucidate their pathogenic impact. Tissue samples from 18 adult wild cats were collected and examined by PCR and histopathology. Five species of apicomplexan parasites belonging to three genera (Babesia sp., Cytauxzoon sp., Hepatozoon silvestris, H. felis, Hepatozoon sp.), as well as two different sequence types of undescribed hemotropic mycoplasmas (designated as type A and type B), were identified in 15 animals (83%). Histopathology revealed no relevant lesions associated with any of the agents detected. The results clearly showed that European wild cats can harbour a broad range of blood-associated parasites and bacteria. However, further studies are required to investigate the possible implication of hematophagous arthropod vectors in their transmission and to clarify the true pathogenic significance of these organisms. Direct transmission of the agents by bites should also be considered as an alternative, non-vectorial route of transmission in wild cats.

Infectious diseases in dogs rescued during dogfighting investigations

Dogs used for dogfighting often receive minimal preventive health care, and the potential for spread of infectious diseases is high. The purpose of this study was to describe the prevalence of infectious diseases in dogs rescued from fighting operations to guide medical protocols for their immediate and long-term care. A total of 269 pit bull-type dogs were seized in a multi-state investigation. Fleas were present on most dogs, but few ticks were observed. Testing performed at intake included packed cell volume (PCV), serology and PCR for vector-borne pathogens, and fecal analysis. The most common infections were Babesia gibsoni (39%), 'Candidatus Mycoplasma haematoparvum' (32%), Mycoplasma haemocanis (30%), Dirofilaria immitis (12%), and Ancylostoma (23%). Anemia was associated with B. gibsoni infection (63% of infected dogs, odds ratio = 2.5, P <0.001), but not with hemotropic mycoplasmas or Ancylostoma. Pit bull heritage and dogfighting are known risk factors for B. gibsoni infection, possibly via blood transmission from bites and vertical transmission. Hemotropic mycoplasmas have a similar risk pattern. Empirical care for dogs from dogfighting cases should include broad-spectrum internal and external parasiticides and monitoring for anemia. Dogfighting case responders should be prepared for mass screening and treatment of B. gibsoni and heartworm infections and should implement protocols to prevent transmission of infectious and zoonotic diseases in the shelter and following adoption. Former fighting dogs and dogs with possible dog bite scars should not be used as blood donors due to the risk of vector-borne pathogens that can escape detection and for which curative treatment is difficult to document.

Intravascular hemolysis associated with Candidatus Mycoplasma hematoparvum in a non-splenectomized dog in the south region of Iran

A 2-year-old male Pekingese dog was referred to Shiraz University's Veterinary Teaching Hospital for anorexia and depression. The case had no history of surgery. Physical examination revealed no abnormalities except mild depression and fever. Small, coccoid, epicellular bacteria were detected on erythrocytes by microscopic examination of the Giemsa-stained blood smears. Abnormalities noted in the complete blood count included regenerative anemia characterized by a marked reticulocytosis. Examination of the plasma showed visual evidence of slight intra vascular hemolysis. In addition, Howell-Jolly bodies, nucleated RBCs, increased immature neutrophils and thrombocytosis were found in this case. The urine was strongly positive for bilirubin, and the urine sediment had abundant bilirubin crystals. For polymerase chain reaction (PCR) purpose, total DNA was extracted from blood sample collected from dog. PCR was positive and phylogenetic analysis of concatenated data showed our isolate clustered within Candidatus Mycoplasma hematoparvum group. Treatment was performed by oral ciprofloxacin and prednisolone. The clinical signs improved after three days. Two month follow-up showed no recurrence. In conclusion, hemoplasmosis should be considered as a differential diagnosis in dogs with hemolytic process and pyrexia. The PCR evaluation for hemoplasma DNA should be included in the investigation of such cases to enable the rapid detection of this infection, which may be more common than previously estimated. Besides, ciprofloxacin might have an effect on treatment of hemoplasma in dogs, however, conducting further case studies are necessary to recommend successful treatment.