HAEMATOLOGICAL CHANGES, CYTOKINE AND ANTIBODY PROFILES IN GUINEA PIGS INFECTED WITH Tunga penetrans

Abstract

Tungiasis is a neglected tropical disease (NTDs) caused by the permanent penetration of the female sand flea into the epidermis of its host and get embedded. The disease causes swelling and intense inflammation associated with the superinfection of bacterial infections; this mechanism of inflammation still remains unknown. This study determined immunological changes; haematological changes, cytokine and antibod of experimentally raised guinea pigs during the natural cause of infection. Three to four weeks old guinea pigs in cages were exposed to Tunga penetrans in highly infested homes for a period four weeks. The animals were examined on a daily basis and blood samples taken before exposure to the fleas and subsequently 5 days after flea penetration. To determine the haematological changes, hematological analyzer was used and serum concentration of selected cytokine and antibody using Enzyme Linked Immunosorbent Assays (ELISA) guinea pig specific kit. Statistical analysis was done using IBM-SPSS software version 25.0 to determine descriptive statistics of means ± SD. Mann Whitney U test was performed to establish differences among the infected and non-infected groups. Post-hoc analysis was done using Wilcoxons signed rank tests to determine the haematological changes, cytokine and antibody profiles which were subjected to pairwise difference between the control and the precise days post-infestation. There was a significant decrease in erythrograms mean values; red blood cells (RBC) (5.02±0.13), haemoglobin (Hgb) (14.66±0.39), packed cell volume (PCV) (39.62±50), mean corpuscular haemoglobin (MCH) (24.27±0.18) and mean corpuscular haemoglobin concentration (MCHC) (33.77±0.60) at {Citation}(p ≤ 0.05). A considerable increase in leukograms mean values, white blood cells (WBC) (9.08±0.35), eosinophil (2.42±15), neutrophils (4.27±0.70), monocyte (0.8±0.05) and lymphocyte (5.6±0.41) as compared with control (p ≤ 0.05). The infected subjects showed a significant elevation of total serum of pro-inflammatory cytokines both at day 10, tumor necrosis factor alpha (TNF-α) (235.39 ± 17 pg/mL), interferon gamma (IFN-γ) (425 ± 5 pg/mL) and significantly higher levels of anti-inflammatory cytokines both at day 15 of post-infestation, interleukin -10 (IL-10) (367 ±17 pg/mL) and interleukin -4 (IL-4) (356±4 pg/mL) as compared to the uninfected guinea pigs (p ≤ 0.05). Moreover, the circulating levels of both antibodies increased significantly following natural infestation at day 15 immunoglobulin E (IgE) (231.9±13 ng/mL) and immunoglobulin G (IgG) (371.9±15 ng/mL). Tungiasis is thus characterized by changes in haematological parameters and the systemic levels of cytokine and antibody indicating an alteration in the underlying immune mechanism to the infection. Profiling of immunological responses implicated in tungiasis unravels the underlying mechanisms on inflammation and development of a diagnostic tool, treatment and control of the infection.