The use of systemic inflammatory index as a predictor for nematodes infection

This was a very surprising conclusion: that the systemic immune inflammatory index goes down in the face of increasing nematode infection. Taken along with the lack of more obvious causes of a decrease, the index becomes highly predictive of what might be otherwise a difficult diagnosis. This explanation is taken from the article and followed by the article abstract:

The current study demonstrated that the SII is a significant predictor of nematode infections in horses. The SII values were significantly lower in horses with nematode infections compared to those without infections. This may stem from an inflammatory response to parasitic burden caused by elevated EPG in horses, potentially overwhelming their immune system or diminishing its efficacy, thereby leading to a lower SII values. Moreover, it may stem from the effects of chronic parasitism resulting from prolonged exposure to parasites, which could inhibit immune function, diminish inflammatory markers, and consequently lower the SII values. These findings were in contrast to the study of (Ye et al., 2022), which indicated that SII may be a potential biomarker for cardiovascular disease (CVD) development and elevated SII value is associated with an increased risk of CVD.
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The use of systemic immune inflammatory index as a predictor for nematodes infections in horses
Parasite Epidemiol Control. 2025 Jul 31:30:e00453. doi: 10.1016/j.parepi.2025.e00453. eCollection 2025 Aug.
Authors
Falmata Kyari 1 , Cephas Joseph Pogu 2 , Ismaila Alhaji Mairiga 2 , Lawan Adamu 2
Affiliations

1 Faculty of Veterinary Medicine, Department of Veterinary Parasitology, University of Maiduguri, Maiduguri P.M.B. 1069, Borno State, Nigeria.
2 Faculty of Veterinary Medicine, Department of Veterinary Medicine, University of Maiduguri, Maiduguri P.M.B. 1069, Borno State, Nigeria.

PMID: 40837204
PMCID: PMC12361788
DOI: 10.1016/j.parepi.2025.e00453

Abstract

Background: Nematode infections are a significant health concern in horses, causing a range of clinical signs and economic losses. Early detection and diagnosis are crucial for effective treatment and management.

Objectives: Examining the application of the systemic immune Inflammatory index (SII) as a predictor for nematode infections in horses, using platelets count, leucocytes count, and neutrophils count.

Methods: A cross-sectional study was conducted on 164 horses, consisting of 66 horses with nematode infections and 98 horses without infections. The SII was computed using the platelets count, leucocytes count, and neutrophils count. Receiver operating characteristic (ROC) curve analysis was used to evaluate the SII’s diagnostic accuracy.

Results: Nematode infections were severe in horses with mixed infections, with an average of 1805.90 ± 292.68 eggs per gram (epg). Notably, among specific species, Cyathostomum spp., exhibited a significantly different average of 2264.29 ± 132.61epg compared to other nematodes. There is a significant negative correlations between the systemic immune-inflammatory index (SII) and the Eggs per gram count for nematodes infections at (r = -0.6023; P < .0001). The SII values were significantly lower (0.06) in horses with nematode infections compared to those without infections (0.19) at p < .001. With an area under the ROC curve (AUC) of 0.990, the SII demonstrated exceptional diagnostic precision. For the SII, the ideal cut-off value is ≤0.108, with a sensitivity of 98.5 % and a specificity of 100 %. The ROC curve was validated using the Youden index (J) with a higher value of 0.9848 indicating better performance.Conclusion: The study demonstrated that the SII is a reliable predictor for nematode infections in horses, using platelets count, leucocytes count, and neutrophils count. The SII is a non-invasive, reasonably priced method for identifying and diagnosing nematode infections in horses.Keywords: Horses; Leucocytes; Nematode; Neutrophils; Platelets; Systemic immune inflammatory index.© 2025 The Authors. Published by Elsevier Ltd on behalf of World Federation of Parasitologists.