Human Invasive Muscular Sarcocystosis Induces Th2 Cytokine Polarization and Biphasic Cytokine Changes, Based on an Investigation among Travelers Returning from Tioman Island, Malaysia

Sarcocystis fusiformis whole cyst antigen activates pro-inflammatory dendritic cells

Sarcocystis fusiformis is a coccidian tissue parasite that causes infection in buffalo in countries such an Egypt, China, Iraq and Iran, resulting in significant economic losses to the agricultural industry annually. There is a lack of studies examining host-parasite interactions at the level of the immune response and the present study investigates the interaction between S. fusiformis whole cyst antigens (SFWCA) and dendritic cells (DCs), cells critical to the activation of adaptive immunity. In this study bone marrow derived DCs (BMDCs) were phenotyped following treatment with SFWCA by measuring cell viability, cytokine secretion, and cell surface marker expression. While SFWCA exhibited cytotoxic effects on BMDCs at higher concentrations, lower concentrations of SFWCA activated pro-inflammatory DCs that significantly secreted interleukin (IL)-12p40, tumor necrosis factor alpha, IL-6 and IL-10. These cells also displayed enhanced expression of TLR4, CD80, CD86 and MHC II on their surface, which is indicative of full DCs maturation. Moreover, SFWCA significantly attenuated the capacity of BMDCs to suppress Th2 associated cytokines, notably IL-5 and IL-13, while simultaneously exhibiting no effects on the secretion of interferon (IFN)-γ, IL-2, IL-17, and IL-10. In conclusion, this is the first study to provide fundamental insight into the activation of DCs by SFWCA, providing us with some awareness into the interaction of the Sarcosystis parasite with its host. The pro-inflammatory inducing ability of this antigen is in keeping with studies performed in other protozoan parasites and therefore understanding these interactions is important in the development of future therapeutic strategies.

Detection of Humoral and Cellular Immune Responses in Buffaloes Naturally Infected with Sarcocystosis with Risk Factor Assessment

Sarcocystosis is a silent, parasitic disease which affects various animal species and causes significant economic losses. It is caused by a number of different intracellular Sarcocystis spp. This study was aimed to detect the host humoral and cellular immune response due to natural infection. Adding to the determination of the infection rate in Monufia Governorate, Egypt. A total number of 127 Egyptian buffaloes (Bubalus bubalis); 30 males and 97 females between 2-11 years of age were examined during 2018. An infection rate of 74% (94/127) was detected by macroscopic examination. The old age females were found to be at a high risk of 90.7% (88/97) in comparison with the young males 20% (6/30). Immunologically, the cellular and humoral immune response was determined using ELISA. A marked down-regulation of the proinflammatory Th-1 cytokine (IFN-γ) and up-regulation of the anti-inflammatory Th-2 cytokine (IL-5) adding to a high level of IgG and IgE were detected in the infected animals compared to the non infected ones. The local cellular immune response in the infected tissues was characterized by an accumulation of mixed inflammatory cells, granuloma formation, eosinophilic infiltration, muscular edema, and necrotic degeneration. In conclusion, the Sarcocystis infection rate in the naturally infected buffaloes in Monufia Governorate was high. This is the first study to provide a fundamental insight into the immune profile in buffaloes infected with Sarcocystis spp. So, it will provide valuable insights to develop novel effective vaccines in future studies. Moreover, sensitive and specific tools should be established for the accurate diagnosis of this disease in the different Egyptian governorates through well-structured serological surveys.

Human Extraintestinal Sarcocystosis: What We Know, and What We don't Know

There are over 150 known Sarcocystis species, and at least one is capable of infecting and causing disease in man. Extraintestinal (muscular) sarcocystosis and intestinal sarcocystosis are the two known manifestations of disease in humans. In this series of six cases and review, we focus on the invasive extraintestinal (“muscular”) form of sarcocystosis in humans. This disease, which until recently was rarely described, has become relevant particularly as an imported condition in travelers due to a recent series of outbreaks reported from Malaysia. Human intestinal sarcocystosis is ubiquitous across the globe. However, absolute numbers of probable and particularly confirmed cases are few, with only several hundred described to date. Characteristically, patients exhibit signs and symptoms either 1–2 weeks after exposure, or after 4–8 weeks. Whether people remain asymptomatic or develop disease apparently depends on the infecting species, host factors, and the inoculum size. The definitive host(s) remain uncertain, and identification of the animal reservoir(s) requires further research. A better understanding of the epidemiology of the disease, as well as its immunological determinants, is hampered by the lack of reliable serological diagnostic methods. Additionally, DNA seems to be contained very effectively within the encysted parasite, thereby rendering PCR detection unreliable. Physicians should suspect the condition in patients with suggestive symptoms and a possible history of exposure. Surveillance networks for imported infectious diseases are formidable tools to help detect and localize outbreaks.