Prevalence and first molecular identification of Sarcocystis species in feces of domestic dogs (Canis familiaris) in Egypt.

BACKGROUND: Sarcocystis species are obligatorily heteroxenous protozoan parasites with predator-prey life cycles. Global Knowledge about the epidemiology and the distribution pattern of different Sarcocystis species in dog feces are very scarce. Therefore, the current investigation was conducted to declare the occurrence of Sarcocystis in the fecal specimens of the most common canids in Egypt, the domestic dogs, and to identify the species present using various parasitological and molecular approaches. METHODS: A total of 100 dog fecal samples were collected and screened using fecal sugar flotation test for the presence of Sarcocystis oocysts/sporocysts. Additionally, thirty samples were used for genomic DNA extraction. The 18S rRNA gene fragment was the target of primers for a PCR, followed by purification and sequencing of the amplicons. RESULTS: Currently, the results obtained reviewed that 4% of fecal samples were positive for Sarcocystis spp. using LM. Additionally, Sarcocystis spp. were verified in sixteen dogs (53.3%, 16/30) using PCR and subsequent sequencing protocols. Statistically, insignificant difference in prevalence of sarcocystosis relative to age and gender was noticed. Morphologically, the detected sporocysts measured 13.2-16.0 × 9.4-11 µm. Based on the 18S rRNA gene, sequencing analysis of amplicons from sporocysts DNA revealed 99.82% nucleotide homology with published S. tenella partial nucleotide sequences from sheep in Iraq and Iran. CONCLUSIONS: This is the first molecular evidence in support of the final host role of domestic dogs in the life cycle of S. tenella in Egypt, which provides a precious diagnostic tool for further epidemiological studies and for the assessment of the effectiveness of control measures for this disease.

Neuropathic pain drives anxiety behavior in mice, results consistent with anxiety levels in diabetic neuropathy patients.

BACKGROUND: Epidemiological studies in patients with neuropathic pain demonstrate a strong association with psychiatric conditions such as anxiety; however, the precipitating pathology between these symptoms remains unclear. To investigate this, we studied the effects of lifelong stress on levels of neuropathic pain-like behavior and conversely, the effects of chronic neuropathic injury on anxiety-like status in male and female mice. In addition, we assayed this link in painful and painless diabetic peripheral neuropathy patients. METHODS: Male and female mice were subject to ongoing life-stress or control living conditions. Baseline sensitivity and anxiety tests were measured followed by spared nerve injury (SNI) to the sciatic nerve. Subsequent sensory testing occurred until 3 weeks after SNI followed by anxiety tests between 4 and 6 weeks after SNI. RESULTS: Levels of tactile or cold allodynia did not differ between adult mice subject to lifelong chronic stress, relative to nonstressed controls, for at least 3 weeks after SNI. By contrast, longer-term neuropathic mice of both sexes displayed pronounced anxiety-like behavior, regardless of exposure to stress. If sex differences were present, females usually exhibited more pronounced anxiety-like behavior. These ongoing anxiety behaviors were corroborated with plasma corticosterone levels in distinct animal groups. In addition, data from patients with painful and nonpainful diabetic neuropathy showed a clear relationship between ongoing pain and anxiety, with females generally more affected than males. DISCUSSION: Taken together, these data demonstrate a strong link between chronic neuropathic pain and chronic anxiety, with the driver of this comorbidity being neuropathic pain as opposed to on-going stress.