Epidemiological Profile of Snakebites Cases recorded at the 3rd Military Hospital Laayoune Morocco between 2011 and 2017

 

Adouani Badr¹, Elwali Abderrahman^1,2, Alaoui Hassan³, Ait Elcadi Mina⁴, Eljaoudi Rachid⁴, Bousliman Yassir⁴

¹3rd Military Hospital Laayoune, Morocco

² Sidi Mohamed Ben Abdellah University, Faculty of Medicine and Pharmacy, Fez, Morocco

³Avicenna Military Hospital, Marrakech, Morocco

⁴ Mohammed V University, Faculty of Medicine and Pharmacy, Laboratory of Pharmacology and Toxicology, Rabat, Morocco

 

ABSTRACT:

Snake bites pose a major public health problem worldwide, this pathology is worrying given the mortality, the morbidity it causes and the limited and often discontinuous availability of antivenomserotherapy. The objective of our study is to reveal the epidemiological characteristics, and the elements of management of Ophidian envenomations in the region of Laayoune in Morocco and to follow the practice of an Inoserp^® MENA antigen after the production stop of FAVafrique^®. This is a retrospective and descriptive study of a series of 23 viperin bite-related cases, which were admitted between January 2011 and December 2017 at the 3rd Military Hospital Laayoune in Morocco. The analysis of inpatient records allowed us to study the circumstances of bite occurrence according to the climatic conditions of the area, biological data, clinical signs, severity criteria and therapeutic treatment. The length of stay in the hospital allowed us to compare two groups; it was lower in the group of patients who received Inoserp^®, compared to the group of patients who received the FavAfrique^®. This reduction in the length of stay in the intensive care unit, which implies a decrease in the use of other therapies, associated biological and radiological assessments, has saved approximately $ 125 per patient. The availability of antivenoms in first aid units and early management has improved the prognosis.

 

 

 

INTRODUCTION:

Snakebites pose a major public health problem around the world, with about five million people affected, 48% of them envenomed, 94,000 to 130,000 deaths each year [1] with 20,000 cases in Africa [2]. In Morocco, the incidence of snakebite infection is estimated at 0.34 per 100,000 inhabitants and 7.2%[3]. Even if this pathology is not very frequent, it remains very worrying considering the mortality and the morbidity that it causes, 400 000 people a year to be amputated or suffering from other serious consequences, such as infections, tetanus, scars and psychological sequelae[1]. It should also be noted the difficulties of therapeutic management and the limited and often discontinuous availability of antivenomserotherapy. The study of the distribution of venomous snakes is an indispensable tool for the establishment of an effective prophylaxis and a good management of the serotherapy against the mortal bites of the serpents.

The objective of our study is to reveal the epidemiological characteristics, as well as the elements of diagnostic and therapeutic care of Ophidian envenomation in the region. The second objective is to assess the work of an antivenomthat was newly registered in the nomenclature of hospitals in Morocco Inoserp^® MENA (Middle East and North Africa) manufactured by Inosan Biopharma, after stopping the production of FAVafrique^® by Sanofi Aventis.

 

Patients and Methods:

This is a retrospective and descriptive study of a series of 23 viperin bite-related cases, which were admitted, between January 2011 and December 2017, to the 3rd Military Hospital Laayoune in Morocco by the first aid units in the region of Laayoune Sakia ElHamra. This region occupies the central position among the three Saharan regions of southern Morocco, it covers an area of ​​140 018 km2, the climate is Saharan, cold in winter, dry and very hot in summer, marked by the scarcity of rainfall and permanent sunshine. The wind, by its regularity and its intensity, is a determining factor in the genesis of the silting phenomenon.

The analysis of hospitalized patients’ records has allowed us to study the following variables:

Ÿ  Patient data: age, sex, underlying pathologies.

Ÿ  The circumstances of occurrence of the bite: the delay of treatment, the place of the bite and the period of the attack according to the climatic conditions of the region. Climatic data were reported by the Tutiempo Network site based on ICAO weather station (ICAO) records: GMML Laayoune / HassanI.

Ÿ  Biological data, clinical signs, severity criteria and complications allowed us to establish a gradation of bites. According to Audebert ^[4], grade 0 corresponds to a white bite; grades 1, 2 and 3 correspond to a minor, moderate and severe envenomation, respectively.

Ÿ  The therapeutic care/treatment and the length of stay in the hospital.

The analysis also compared the efficacy and cost of two antivenom serums between two periods. The first period was from January 2011 to May 2016 (n = 18), the nationally available antivenom serum was FAVafrique®. The second period, between June 2016 and December 2017 (n = 5), was marked by the acquisition of Inoserp®. A first antivenom serum was systematically administered to patients by the region's first aid units. A second vial was administered according to clinical and biological signs at admission to our hospital.

All information was recorded on cards, transferred to a database, and analyzed by SPSS 17.0 statistical processing software.

RESULTS:

In our study, 23 snake bite cases were collected between 2011 and 2017. All patients were male, with an average age of 31 ± 9 years. The average time between the bite and the consultation in our hospital was 7 ± 4 h. The average length of stay in the hospital was 8 ± 5 days. The underlying pathologies were cholecystomy (n = 1), varicose veins (n ​​= 1) and one diabetic case (n = 1). The general characteristics are summarized in Table 1. 

Table 1: General Characteristics of Patients and Bites

Variables	Number of cases (%)	p
Sex male	23 (100)
Age
< 20 years old	1 (5)
between 21 and 30 years old	14 (64)
between 31 and 40 years old	3 (14)
between 41 and 50 years old	3 (14)
> 50 years old	1 (5)
The seat of the bite		0,210
Upper body parts	8 (34,8)
Lower body parts	15 (65,2)
The period of the attack		0,011
Day attack	5 (21,7)
Night attack	18 (78,3)

The high number of bites was observed in 2013 (Figure 1).

 

 

Figure 1: Distribution of the number of bites per year

All bites were between May and October with a peak in July (Figure 2). 

 

 

 

Figure 2: Distribution of the number of bites per month (TM: maximum temperature (°C), Tm2: minimum temperature (°C), H: relative humidity average (%), VM: maximum wind speed (Km/h).

 

There is a correlation between the minimum temperatures displayed at night and the number of bites (p = 0.035), there is also a correlation between the maximum wind speed and the number of bites (p = 0.017). The seat of the bite was 65.2% in the lower extremities (lower body parts). Snake attack was for 78.3% of patients at night with a significant difference between night and day attack (p = 0.011). The majority of the bites were grade 1 for 61% of patients (Figure 3).

 

 

Figure 3: Clinico-biological gradation of bites

 

So, the suggestive clinical signs were edema in 65%, pain in 35%, hypotension in 15%, and bleeding in 13% of patients (Figure 4).

 

Figure 4: Clinical Signs of Bites

 

The pathological biological signs were marked by a prolonged APTT (activated partial thromboplastin time) for 14%, a PR (prothrombin ratio) decreased by 56%, thrombocytopenia for 23% and hyperleucocytosis for 39% of patients (Figure 5).

 

 

Figure 5: Biological signs (hemostasis, coagulation and leukocytes)

 

 

 

 

Therapeutic treatment was based on antivenom for 65%, analgesics for 61%, antibiotics for 30%, anticoagulants for 22%, and antitetanus serum for 13% of patients (Figure 6).

 

 

Figure 6: Percentage of patients who have been treated with medications

 

The evolution was favorable for almost all patients. However, a complication type of pulmonary embolism was noticed after ten days of the bite for a single patient. The length of stay in the hospital for the group of patients who received a FAVafrique^® antivenom serum was more than 7 days for 55.6%, for the group of patients who received the Inoserp^® anti-venom serum, it was more than 7 days for 20% of patients, a significant difference between the two groups was observed (p = 0.044).

 

DISCUSSION:

The majority of epidemiological studies report a high snake bite number in spring and summer [3, 5-7] resulting not only from higher activity of snakes and humans, but also from variations in climatic conditions: temperatures, relative humidity, and wind speed. There is a statistically significant correlation (p = 0.035) between temperature rise, especially at night, and snakes attack. The rise of the wind speed is a predominant criterion in the number of snake attack, there is a statistically significant correlation (p = 0.017); when the speed increases, the lifting of the sand grains and their transport becomes very easy to trigger a high movement and thus a hectic movement of snakes. There was a statistically significant (p = 0.011) increase in snake attack at night compared to the day. As in our study, the most common bite site is the lower limb [8]; this area is probably more in contact with the snake at the time of the attack.

 

The clinico-biological signs were marked mainly by signs of inflammation, hemostasis disorders and thrombocytopenia. They are due to the composition of the venom of the snakes in action. Snakes in Morocco are represented by 25 species belonging to five ophidian families: Leptotyphlopidae, Boidae, Colubridae, Elapidae and Viperidae. The venomous snakes are represented by two families: Elapidae with a single species (Naja hajalegionis) and Viperidae with 7 species (Echis carinatus, Bitis arientans, Cerastes cerastes, Cerastes vipera, Vipera latasti, Vipera mauritanica and Vipera monticala) ^[9]. Elapidae venom contains neurotoxins and phospholipases that cause neurological and respiratory disorders ^[10]. The biochemical structure of the venom secreted by the venomous gland of vipers is variable; it is composed of several enzymes and toxins. These proteins are generally nucleosidases, disintegrins, phospholipases A2, type-C lectins or serine proteinases. They act on platelets, plasma coagulation and on fibrinolysis ^[11]; metalloproteases are responsible for edema and hemorrhage ^[12]. Their function is to degrade the proteins of the extracellular matrix; they activate certain factors of the coagulation, including FX and FII, causing systemic bleeding ^[13].

Antivenom is the mainstay of the therapy for snake bites, Inoserp® and FAV Afrique®, used in our hospital, are polyvalent antivenoms composed of highly purified F (ab ') 2 immunoglobulin fragments produced by the immunization of horses. Inoserp® is active on the venom of 28 species of snakes and covers almost all existing venomous species in Morocco, while Fav Afrique® is active on the venom of only 4 species of snakes, it is inactive on the venom of Cerastes "horned viper", the most dangerous species in our region whose venom is particularly toxic and causes very severe envenomation (Table 2). 

 

Table 2: Comparison of the action spectra (+) between FAV AFRIQ^® and INOSERP^® for snakes present in Morocco

Snakes species	Inoserp®	Fav Afrique®
Naja haje	+	+
Bitis gabonica		+
Bitis arietans	+	+
Cerastes cerastes	+
Cerastes vipera	+
Echis leucogaster	+	+
Maprovipera mauritanica	+
Macrovipera deserti	+
Vipera latastei	+

The control strategy in this highly endemic area was based on the routine administration of the first anti-venom serum for all patients by the first aid units only 65% ​​of the patients required the administration of the second vial in our hospital.

The length of stay in the hospital was lower in the group of patients who received Inoserp®, compared to the group of patients who received FavAfrique® (p = 0.044). This reduction in the length of stay in the intensive care unit, which implies a decrease in the use of other therapies and other associated biological and radiological assessments, has saved approximately $ 125 per patient.

To prevent snake bites, some rules that stem from this study can be taken into account. It is advisable to wear long clothes and high and strong shoes. Be more vigilant in spring and summer and especially at night where it necessitates moving with a lamp.

 

CONCLUSION:

The severity of snakebites in our study was benign as more than 80% of envenomation cases were grade 0 and 1. The availability of antivenoms in first aid units and early treatment helps to improve the prognosis. The collection of these epidemiological data is undoubtedly an essential tool for the development of an antivenom serum adapted to each region.

 

CONFLICT OF INTEREST STATEMENT:

We declare that we have no conflict of interest

 

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Accepted on 24.11.2017           © RJPT All right reserved

Research J. Pharm. and Tech 2018; 11(5): 1752-1756.