A case series of samar cobra, Naja samarensis Peters, 1861 (Elapidae) envenomation

Characteristics of snakebite patients due to Naja samarensis in the Philippines: a prospective hospital-based study

BACKGROUND

Little is known about snakebites by Naja samarensis, a species unique to the Philippines. The aim here is to describe the clinical and epidemiological characteristics of patients bitten by this medically important cobra in the Eastern Visayas.

METHODS

A hospital-based prospective study analysed the features of snakebite patients attending Eastern Visayas Medical Center between June 2022 and May 2023. Logistic regression analysis identified the factors associated with severity.

RESULTS

A total of 175 snakebite patients with five fatalities were included. Naja samarensis was most commonly implicated (n=49, 28.0%), although it could be definitively identified, by examining photographs of the snake responsible, in only four cases. The N. samarensis bites occurred in grass or rice fields, in daytime, and during farming activities, but the people bitten were most frequently students (34.7%) who were bitten at home (36.7%). Patients bitten by N. samarensis often presented with cytotoxic (63.3%) and neurotoxic signs (46.9%). Traditional remedies were common, resulting in delayed presentation to the hospital. Bites by N. samarensis, and older age (>44 y) were independently associated with severity (adjusted OR of 10.33 and 7.89, respectively).

CONCLUSION

Naja samarensis is a major cause of severe snakebites in this region. Pre-hospital treatment frequently involves wasted time and unproven traditional methods. Enhancement of public awareness is urgently needed. Development of a diagnostic test for species identification is warranted to improve future surveys and management.

Neurotoxic snakebite envenomation treated with Philippine cobra antivenom in the eastern Visayas: a descriptive study between 2016 and 2020

Introduction

There is a significant shortage of observational studies on neurotoxic snakebite envenomation in the Philippines. This lack of data, especially concerning treatment using Purified Cobra Antivenom (PCAV), has prompted the initiation of this foundational study.

Methods

The target population included snakebite patients admitted to the Eastern Visayas Medical Center and treated with PCAV between 2016 and 2020. A retrospective chart review was conducted for data collection. The investigation analyzed the hospital stay and patient features of individuals who were administered either lower or higher doses of PCAV.

Results

Eighty-two patients were identified during the study. Of these, 27 (33%) were under 20 years of age and 50 (61%) were male. Most patients, totalling 75 (92%) were hailed from rural areas. Of the 82 patients, 59 (72%) received one or two ampoules of PCAV during the course. However, patients who received more than two ampoules had a longer median hospital stay than those who received less than three ampoules [96 h (interquartile range, IQR 66-122) vs. 125 h (IQR 96-218), P = 0.038]. The study reported five in-hospital mortalities (6.1%).

Conclusions

The individuals who needed a high dosage of PCAV tended to have more extended hospital stays, yet over 70% of the patient population required a lower dosage. To gain a clearer understanding of the burden of neurotoxic snakebites and determine the optimal PCAV dosage based on disease severity in the area, a more comprehensive, prospective study is recommended.

Inhibition of bacterial biofilms by the snake venom proteome

Snake venoms possess a range of pharmacological and toxicological activities. Here we evaluated the antibacterial and anti-biofilm activity against methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) of venoms from the Samar spitting cobra Naja samarensis and the Puff adder Bitis arietans. Both venoms prevented biofilm production by pathogenic S. aureus in a growth-independent manner, with the B. arietans venom being most potent. Fractionation showed the active molecule to be heat-labile and >10 kDa in size. Proteomic profiles of N. samarensis venom revealed neurotoxins and cytotoxins, as well as an abundance of serine proteases and three-finger toxins, while serine proteases, metalloproteinases and C-lectin types were abundant in B. arietans venom. These enzymes may have evolved to prevent bacteria colonising the snake venom gland. From a biomedical biotechnology perspective, they have valuable potential for anti-virulence therapy to fight antibiotic resistant microbes.