Descripción
GENERAL INFORMATION.
• Commercial name: BIORAT.
• Class: Biological rodenticide.
• Toxicology class: Slightly toxic( cat. IV).
• Types of formulate: Granules.
• Appearance: Color - brown.
Aspect - wet grain.
Smell - characteristic
• Active ingredient: Salmonella enteritidis var. Danysz, lysine negative, phage type 6a.
• Inmunodepressor: Hydroxycoumarin salt.
• Description:
BIORAT is a biological rodenticide. Its active principle is the bacterium Salmonella enteriditis var. Danysz lysine negative, which is included in a bait of un-husked rice. This bacterium is specific for the families Muridae and Cricetidae and its effectiveness ranks between 95-100 % in field and lab mice as well.Its innocuousness for man and other animals has been proved. This product does not alter the ecosystem.
• Solubility: not soluble in water, not soluble in organic solvents.
• Effect on metals: not corrosive.
• Compatibility: May not be mixed with any other pesticide.
• Packing: 50g, 250g, 400g, 1kg, 4kg
• Stability:
This product maintains its effectiveness for one year at 2 to 80 C
First aid:
In case of contact with skin, wash thoroughly with soap and water. After an ingestion and a possible intoxication take the patient to the doctor who will be given a product label copy.
• Antidote: In case of excessive ingestion, administer vit.K according to prescribed doses and routes.
• Effective dose:
Biorat is used for the control of rats and mice in livestock, agricultural and city objectives.
Place 50 g of BIORAT in dens, footpaths and places protected from the sunlight in a
circular Blockade form, separated 2 to 5 meters from each other, in the late afternoon.
The treatments can be done in any season of the year.
Carry out only one application of the product, effective for not less than six months
(integrated control).
• Action mechanism.
The substance en trial contains enterotoxines which cause lesions to the intestinal mucous membrane allowing the bacteria to penetrate into the blood system, colonization of several target organs such as the heart, spleen, liver and kidneys and therefore provoking a systemic infection.
It is important to stress the fact that, in spite of the lack of information about the probability of mutations in this bacterium, our laboratories have carried out some tests to guarantee that this strain is not mutagenic. To that effect S. enteritidis was inoculated into media from different origins in which there were intentionally lacking some nutrients .
• BIORAT. Toxicological test
Acute oral toxicity/pathogenicity of the monopathogenic bacterium Salmonella enteritidis variety Danysz, lysine negative, phagotype 6 a, active biological agent in the biological rodenticide BIORAT, in mice CENP: NMRI
Objectives.
To perform clinical observations daily, taking into account behavior and habits expressed by exploration, feeding, water consummation, toilet, rest and thermoregulation activities for detecting any sign of toxicity.
To collect animal excrements for estimating clearing rate of substance under trial after oral administration
Conclusions.
Under the experimental conditions of this essay and according to assessments and results, the following conclusions can be backed up:
Product under essay killed 100 % animals in the treated group.
The microorganism infected all organs analyzed with a similar magnitude in inoculated animals.
A definite clearing of the product could not be demonstrated.
Lesions found during anatomical – pathological are characteristic of a Salmonellosis
Salmonella enteritidis var. Danysz lysine negative phage type 6a.
Acute oral toxicity in rabbits
Objectives
General
To determine the acute oral toxicity in rabbits of Salmonella enteritidis var. Danysz lysine negative phage type 6a.
Conclusions
Salmonella enteritidis var. Danysz lysine negative phage type 6a in a single dose used in rabbits of both sexes by the oral route does not give rise to lethality.
The administration of a dose of 108 CFU/mL does not give rise to macroscopic modifications of the examined organs.
The dose of Salmonella enteritidis var. Danysz lysine negative phage type 6a administered gives rise to no variations of the clinical signs or of the normal corporal weight gain in animals of both sexes.
BIORAT. ACUTE ORAL TOXICITY IN RABBITS
Objectives
To evaluate the acute toxicological behavior of BIORAT in the selected animal species.
Conclusions
BIORAT in a single dose used in rabbits of both sexes by the oral route does not give rise to lethality.
The administration of a dose of 108 CFU/mL does not give rise to macroscopic modifications of the examined organs.
The dose of BIORAT administered gives rise to no variations of the clinical signs or of the normal corporal weight gain in animals of both sexes.
Mutagenic assessment of the monopathogenic bacterium Salmonella enteritidis variety Danysz lysine negative phagotype 6a, active biological agent of the biological rodenticide biorat. micronuclei assay in bone marrow
Objective
Aiming at the determination of the genotoxic potential of the monopathogenic bacterium Salmonella enteritidis variety Danysz lysine negative phagotype 6a, active biological agent of the Biological Rodenticide BIORAT, this product was assessed using Micronucleus Essay in Bone Marrow of Mice for estimating lic induction of micronucleus in polychromatic erythrocytes and the cytological effect en the relation polychromatic - normochromatic erythrocytes.
CONCLUSIONS
Considering above. it can he concluded that (under the assay conditions and dose level) the substance did not show any Clastogenic or Cytotoxical effects on bone marrow in mice.
“Evaluation of the ophthalmic and dermal irritating potential of the biological rodenticide BIORAT( inoculum and finished product) and of the viability of Salmonella enteritidis var. Danysz Lysine-negative on the ocular mucose”
Objectives:
To determine the dermal and ophthalmic potential of BIORAT (inoculum and finished product) on the ocular mucous of rabbits and of the viability of Salmonella enteritidis contained in the product.
Conclusion
BIORAT does not give rise to dermal irritation in the tested pattern.
BIORAT does not give rise to ophthalmic irritation in the tested pattern.
Salmonella enteritidis variety Danysz lysine- negative was viable after 96 hours, in coincidence with the highest observed irritability, which was always within the not irritating values.
Evaluation of the safety for humans of the ingestion of Salmonella enteritidis, var Danysz, lysine negative, phage type 6 a
Objectives.
General:
To evaluate the possible safety of Salmonella enteritidis, var Danysz, lysine negative, phage type 6a.
Justification.
In Cuba the biological rodenticide BIORAT has been used for more than 28 years for the elimination of rodents without damage to the health of human beings and other animals. Nevertheless, there have been studies made to prove scientifically its safety for human beings, considering that one of its components is live Salmonella enteritidis.
Cuba, a pioneer in biological controls, has been able to arouse the interest of some Latin – American countries in the utilization of this product as a means of diminishing their rodent population. The use of the Cuban product by other countries involves the acquisition of hard currency for our country and it is, therefore, necessary to establish beyond doubt the characteristic of this product and its safety by means of adequate research experiments
Conclusions
There were not hemocultures or coprocultures positive to Salmonella, neither in the test group nor in the control group.
The rest of the tests do not show significant differences between the test group and the control group. The differences in the number of polymorphonucleates lose soundness when the fact that they were observed both at the beginning of the trial (when the inoculum had not yet been administered ) and at the end of the period, and the difference in the number of leukocytes between both groups are observed only at the beginning of the test.
t is our criterion that the ingestion of Salmonella enteritidis,var. Danysz,lysine negative, phage type 6 a does not seem to give rise to any pathogen effect in humans, according to the demonstration of the Clinical Trial.
Carcinogenicity of the biological rodenticide biorat
Carcinogenicity studies are undertaken in an unavoidably in all cases in which products are use for a long time, with the possibility of the onset of chronic action; when the product is used preventively in several doses and when the biological products to be used have a certain degree of homology with the human genome.
The indications for the use of BIORAT contemplate its use for only one time and in view of the effective control it achieves, it is not necessary to use it again for six or 8 months. Besides, the genetic material of the microorganism it contains has no similitude at all with that of humans.
In none of the tests performed with this product, both in the laboratory and in massive applications with different animal species and with humans, has there been any evidence or suspicion of the possibility of tumorigenicity.
In the literature, we have not found any report linking Salmonella enteritidis to the onset of tumors in animal species or in humans.
Toxicological Criteria about the product BIORAT
Warfarin is a product classified as a rodenticide. It is widely used and it is a derivative of coumarin. It has a wide safety margin as compared to other chemical products used for the same purpose.
Rodents must ingest the product for 3 to 10 days in order for lethal levels to be achieved. Repeated doses of the product are necessary for children to develop signs of poisoning.
Repeated doses inhibit normal coagulation and eventually lead to death by hemorrhage.
The onset of hemorrhages requires significantly long ingestion periods. Doses of 1 – 2 mg/Kg/day maintained for one week give rise to severe hemorrhage.
Pharmacokinetics
Warfarin is absorbed in 2 to 3 hours in the intestinal tract. Dermal absorption in humans has not been established.
Its half-life period is 42 hours and its toxicity remains for a few days.
According to its toxicity, Warfarin is classified as a LOW TOXICITY (LD50 500 – 5000 mg/Kg of body weight) product.
Antitoxic Treatment
When there are doubts about the amount of Warfarin ingested or about the health conditions of the patient, oral administration of Fitonadione (Vitamin K1) protects against the anticoagulating effect.
Conclusions
Exposure of the population as a whole to Warfarin-containing rodenticides by the air, by drinking water or in food is very low and it does not constitute a significant risk for human or animal health.
Poisoning accidents can take place in case of massive ingestion or massive dermal exposure during the manufacturing or formulation stages of the highly concentrated product.
Determination of the capacity of Salmonella enteritidis var. Danysz lysine negative, to penetrate the placental barrier of the guinea pig.
Objectives
The scope of our work is to determine the capacity of the bacterium Salmonella enteritidis to colonise the primary organs of the guinea pig, to cross the placental barrier, and to induce affectations at a fetal level.
CONCLUSIONS
The results obtained evidence the invasive inability of the bacterium Salmonella enteritidis var. Danysz, both to colonise the internal organs of pregnant females, and to cross the placental barrier and affect the offspring which makes it innocuous for these animals.
Acute dermal toxicity test of the biological rodenticide biorat in albino rabbits n.z.
Objectives.
To carry the daily clinical observations, taking care of the behavior and habits by means of the exploration, grooming, rest and thermorregulation activities, in order to detect toxicity signs.
To determine if the application of a dose of the product on the shaved skin of the rabbits gives any kind of affectation or local change at the application site.
In case of affectation or local change in the application site, study the possible histological variations that may take place in the skin in the application area and healthy area, as well as, to determine the alterations in other organs.
CONCLUSIONS
All of the above leads to the conclusions that on the conditions of the test the
BIORAT:
Did not produce variations in the animals behavior, nor in the body weight values.
Did not produce anatomo-pathological alterations.
Determination of the possible sensitizing effect of BIORAT, a product of LABIOFAM
Objectives: To determine the potential for bringing about or developing skin sensitization reactions, (Allergic Contact Dermatitis), an important element in the evaluation of toxicity in products that are going to be used as pesticides.
Conclusions:
No erythematous or edematous skin lesions were found in the animals ( treated and control).
No animals was sensitized due the application of BIORAT.
The application of BIORAT did not affect the weight gain of the guinea pigs used in the test.
General conclusions
According to the results of the test using guinea pigs as experimental animals, the product BIORAT is not a potential allergen, so that it passes SATISFACTORILY the SENSITIZATION test.
• Environmental Effects:
SAFETY OF S. enteritidis var. Danysz lysine-negative.
The safety of S. enteritidis var. Danysz lysine-negative has been sufficiently documented for domestic animals by Bykovski and Kandyvin (1988).
In Cuba, Espino et al (1970) stressed the fact that oral consumption of very big doses of S. enteritidis var. Danysz lisine-negative does not cause symptoms of the disease in domestic animals (poultry, swine, rabbits, sheep, bovines, horses, cats, dogs and guinea pigs).
S. enteritidis var danysz lysine-negative is not an invasive strain, except in murid rodents and therefore it does not cause the clinical symptoms of salmonellosis, nor can it be isolated from the internal organs of animals not being murid rodents, nor does it bring about a serologic response in the non-animals that have been exposed orally.
As we will see now, the researches done in Cuba (LABIOFAM) and abroad fully proved all of the above.
Fustes et al. (1995) evaluated the safety of S. enteritidis var Danysz lysine-negative in SPF chicks, one day old, inoculating 60 of them orally with 0,5 mL of a culture containing 1 x 108 CFU/mL .The clinical symptoms of salmonellosis, anatomopathologic lesions compatible with salmonellosis, isolation of salmonella from the spleen, liver and kidney when the chicks were necropsied at the age of 7 to 42 days old (10 chicks per week). The gain of weight was also taken into consideration. In this case also, 60 animals were used and administered placebo in order to assess the establishment and persistence of S. enteritidis var. Danysz lysine-negative in the intestine of the chicks. Samples from the cloaca of 10 chicks were taken daily by hyssoping.
The results were:
There was no persistence of S. enteritids var. Danysz lysine-negative in the intestine of the chicks, the maximal period of excretion being of 5 days in one chick.
There were no clinical symptoms compatible with avian salmonellosis (depression, anorexia, delay in the growth, diarrhea and death).
There were no macro- or microscopic pathological lesions compatible with avian salmonellosis.
Salmonella enteritidis var Danysz lysine-negative could not be isolated from the internal organs of the animals.
There was no difference in the gain of weight between the two groups (control and challenged group).
Gutiérrez et al (1992), studied the safety of S. enteritidis for poultry, using various ways of infection (oral, subcutaneous, and by contact). A group of 120 animals of light breed, 3 weeks old, were divided into six groups of 20 animals each. In every case a dose of 3,3 X 109 CFU/mL was used. The experimental treatments were:
1. Water consumption for 5 days.
2. Concentrate consumption for 5 days.
3. BIORAT consumption for 5 days.
4. Remaining together with mice (20) consuming BIORAT.
5. Subcutaneous inoculation (0,5 mL).
6. Non-challenged control.
The results were:
1. There were no clinical symptoms nor anatomopathologic damages ascribable to avian salmonellosis (Padrón, 1990; Shivaprasad et al, 1990, Gorham et al, 1994) at the end of 6 weeks of post-challenge observations.
2. As a result of the incubation in enriched media, before the sewing in selective media, ittlheight 280 the results were:
• There were no clinical symptoms nor anatomopathologic damages ascribable to avian salmonellosis (Padrón, 1990; Shivaprasad et al, 1990, Gorham et al, 1994) at the end of 6 weeks of post-challenge observations.
• Was not possible to isolate S. enteritidis from the internal organs of the animals 7, 14, 21, 28, 35, and 43 days after the challenging.
• The consumption of BIORAT or contaminated concentrates and drinking water with S. enteritidis do not induce the production of detectable antibodies by the agglutination reaction, using antigens of S. enteritidis and S. pullorum.
• The poultry living with rats that consumed BIORAT and died and from which S. enteritidis was isolated (from the internal organs), did not show clinical symptoms of salmonellosis, nor serologic responses detected by the agglutination reaction using antigens of S. enteritidis and S. pullorum, in the exposed animals.
The fowl inoculated subcutaneously did not show symptoms of salmonellosis, but it was possible to detect serologic responses in the agglutination test with antigens of S. enteritidis and S. pullorum that reached the maximum titles (microagglutination) two weeks after the challenging, with a significative decrease of the titles and of the percentages of positive animals four weeks after the challenging.
One milliliter S. enteritidis was administered to 25 laying hens (x= 34 weeks), orally (1 x 108 CFU/mL) which were serologically negative (Plate agglutination) when necropsies 4 weeks after the inoculation. The results were:
- There were no clinical symptoms of salmonellosis.
- There were no anatomopathologic lesions, nor isolation of S. enteritidis from the spleen, liver, ovaries, or oviduct on necropsy.
- There were no differences in the production of eggs for 30 days after inoculation.
- There were no positive serologic reactions (Plate agglutination) 30 days after inoculation, using the antigen of S. enteritidis and S. pullorum.
The literature describes that in chickens, Salmonella enteritidis phage type 4 causes depression, anorexia, limping, delays in growth (O'Brien, 1988; Likvis, 1988), death and pathological alterations (Gorham et al, 1994). Shivaprasad et al (1994) showed that the oral inoculation of S. enteritidis PT8 caused depression anorexia, diarrhea, decrease in the production of eggs and sometimes death, with isolation from liver, spleen, peritoneum, ovaries and oviducts. Gast and Beard (1990) had similar results.
From all the above data, it is possible to assert that S. enteritidis is not capable of infection persistently the digestive tract in poultry, thus demonstrating the safety of S. enteritidis. The fact that the clinical disease and the mortality are characteristic of the oral infection in the highly susceptible one day old chicks (Hassan, Porter, Curtis, 1993). These animals are very susceptible to paratyphoid salmonellae up to the age of 7 days.
RESULTS OF THE EVALUATION OF ACUTE TOXICITY IN FISH OF SALMONELLA ENTERITIDIS VAR. DANYSZ (LYSINE NEGATIVE) CONTAINED IN THE BIOLOGICAL RODENTICIDE BIORAT.
OBJECTIVES
The evaluation of the acute toxicity of Salmonella enteritidis var. Danysz
in fishes had as main objectives the following:
To evaluate the behaviour of fishes in the presence of Salmonella
enteritidis var. Danysz (lysine negative).
The specific objective is:
To evaluate the behaviour of different species in the presence of Salmonella enteritidis var. Danysz (lysine negative).
Results and conclusions
Behaviour of the fishes.
78 hours after the beginning of the evaluation of acute toxicity of Salmonella enteritidis in fish, one of the control Tilapias died (0,69% of the non-inoculated animals). In spite of the fact that the animal had not been treated, the internal organs were cultured. The cause of death could not be determined. It is possible that although its behaviour including the ingestion of food was normal after the adaptation period, this was only an apparent adaptation to captivity, for it was one of the most aggressive Tilapias. As a whole, as indicated before, the adaptation of Tilapias was more difficult. The rest of the fished had a normal physical appearance; none showed lack of reaction or loss of equilibrium or any other characteristic not corresponds with the normal behaviour of the species.
The oxygen in the water was always above 65% of the air saturation value. The concentration of ammonium did not augment, but nitrites (NO2) and nitrates (NO3) did starting 48 hours after the beginning of the experiment. This happened mainly in the aquaria with carpas and tilapias. The values of NO2 and NO3 were 0,05 - 1 mg/liter (ppm) and 50 - 100 mg/liter (ppm) respectively. Water thermometers registered a temperature of 23 - 25 ºC during the experiment, while the pH was 7.0 - 8,2.
The impact of biological rodenticide BIORAT on populations of rodents settled in some crops was determined; these crops are highly infested with Sigmodon hispidus, a very common vector in various Central American countries. The trapping technique and the appraisal of damages allowed to calculate the index of infestation which range from 75 to 90 percent in three crops. Twenty for to 36 kg of BIORAT were applied to 6 ha planted with Cucumis sativus (cucumber), Ipomoea batata (sweet potato) and Ananas comusus (pineaple). This action brought about that the rodent population in such crops reduced the potential damage and consequently, index of infestation was reduced by 94.6 to 98 %; therefore, the residual population left amounted from 2 to 3.5 %, meaning that damages were under the economic threshold. Generally speaking, the results were similar to those of other countries.
• Efficacy
NOTES ABOUT THE EFFICACY AND SAFETY OF THE BIOLOGICAL RODENTICIDE "BIORAT".
The rodents (Rodentia) are, with big differences, the most numerous of all mammals, both in number of species and in absolute number. However, some species are particularly well adapted to thrive in the rich environment supplied by human establishments and by agriculture and this fact has led to their being called "plagues". In this category, among others, there are three species of murids (Muridae)
•Rattus rattus Linnaeus (roof rat)
•Rattus norvegicus Bekenhout (grey rat or drain rat)
•Mus musculus Linnaeus(domestic mouse)
The above-mentioned species are known as commensal rodents and in the biological sense, this is so because they live in close relation to man and share his food. Therefore, they have been called domestic, peridomestic or sinantrophic rodents. Sometimes the three commensal species do not live as such, either in crop areas or in places with no crops, away from human beings.
Since the most ancient times, man has felt the need to fight the commensal rodents. The first reason for this are the economic loses that they cause to the crops, stored grains and the damages to buildings and installations.
Man has also established the nexus between some diseases and rats and mice. Nowadays we know that the murid rodents can be vectors of more than 60 diseases, among others:
• Leptospirosis
• Bubonic Plague
• Haemorrhagic Fever
Up to the present, in most cases, the commensal rodent plagues have been fought through the use of rodenticide baits, of rapid or slow action, which use some of the various toxic substances that are known today for the struggle against rodents and which have caused so many poisoning accidents among human beings and domestic animals.
Due to their dangerous characteristics, rapid action rodenticides have been substituted by slow action or multiple doses rodenticides. However, the use of these toxic substances could have great negative effect on the quality of the ecosystem.
Another alternative for the control of commensal rodents is biological control (microbiological control).
In 1893, in France, Danysz isolated from the vole, a bacterium and used it against the field rats and some species of rodents in France, Switzerland, Denmark, England and other European countries. At the same time in Russia, S. S. Merezhkovski (1893) also isolated a bacterium capable of killing rodents.
During an epizootic that caused a great mortality among grey rats in Saint Petersburg, Russia, in 1897, V. L. Isachenko isolated from the organs a bacterium which he named "decumanicidum" (today Salmonella enteritidis var danysz lisina negativa).
In 1892, Loffler, in Germany, isolated a bacterium from mice that died in an epidemic form and recommended its use for the control of murid rodents, Salmonella typhimurium.
At the beginning of the last century, there were multiple isolations of bacteria that were used for the control of rodents in Germany (Laser 1892, 1894; Dumbar, 1906, England; Bahr, 1905, 1917, 1922, Switzerland; Neiman, 1906, Denmark).
Unfortunately, when the beginnings of the development of the microbiological method are analysed historically, there are negative references to the uses of micro-organisms that proved to be, in fact, they are, pathogenic for other animal species, man included.
These facts, together with the deficient characterization of the micro-organisms employed, from the biochemical, serologic, and safety point of view, gave rise, long time ago to criticism in relation to the use of these methods. More so in this case, because the micro-organism was identified as Salmonella according to the serologic classification of Kauffmann-White and that, certainly, in this group there are varieties that are pathogenic to man and other animals, as is the case of S. dublin, S. enteritidis Breslau, S. enteritidis Gelner, S. enteritidis Jena, and others.
The first experiences relating to the introduction of the microbiological method for the control of murid rodents in Cuba date back to 1967 and since 1985, the biopreparation BIORAT has been industrially produced. BIORAT has been massively used in Cuba and up to the present moment, its use has not been related to epidemic outbreaks of salmonellosis in the human or the animal population
EFFICACY OF THE BIOLOGICAL RODENTICIDE BIORAT (LABIOFAM)
The biological rodenticide BIORAT is manufactured so as to obtain an efficacy of more than 75%.
BIORAT has shown its efficacy in some practical very different conditions (Cuba, Bolivia, Ecuador, Nicaragua, Peru, Dominican Republic, Salvador, Costa Rica and Vietnam) in campaigns against:
• Rattus norvegicus
• Rattus rattus
• Rattus flavipectus
• Rattus exulans
• Rattus argentiventer
• Mus musculus
• Orysomys sp.
• Sigmedon sp.
• Calomys callosus
• Akodon sp.
• Helochihis brasiliensis
• Proechimys sp.
The results of the efficacy of the biological rodenticide BIORAT in Peru and Bolivia, by the trapping method are the following:
The biological rodenticide BIORAT was used in Peru in 1994 during the control of the outbreak of Bubonic Plague in the province of Lambayeque; and in 1995 it was used in Nicaragua for the control of the outbreak of Leptospirosis in some regions of that country.
In both cases, in spite of the great amounts used (40 and 35 tons respectively) and of the co-operation of the people of the communities for the application, there have been, up to this moment, no reports of cases of human or animal salmonellosis.
In Bolivia in 1995, BIORAT was used in the San Pedro Prison and in the General Hospital (La Paz), without any case of salmonellosis among the persons in either of the two places.
Another way to prove the efficacy of BIORAT is the evaluation survey, as in the case of Mórrope. The district of Mórrope, in the Peruvian province of Lambayeque, has 23,113 inhabitants in 45 villages scattered in a very extensive geographical zone (1041 km2, plain, with characteristics going from those of a true desert to semi-desert, with carob trees as the only shrubs present.
The breeding of domestic animals is among the main economical activities of the zone: bovines, sheep, horses, guinea pigs and poultry.
That is why the people in Mórrope were against the use of chemical rodenticides and for the introduction of BIORAT in the region.
According to the estimates of the survey (Table No. 2), the efficacy of BIORAT was 95.4%. There were no reports of any kind of accident neither in the human or the animal population.
The practical use of BIORAT in Cuba, for more than 28 years and its use in different countries with different climatic conditions in the struggle against more than 13 species of rats and mice, allow us to assert that BIORAT is a rodenticide with a proved efficacy.
Control of the Outbreak of Leptospirosis. Achuapo, Nicaragua, 1995.
Background and Basic Information
In the last years, climatic factors, mainly abundant rainfall, together with the production and accumulation of agricultural products, have determined a massive reproduction of rodents and their migration to zones that have allowed a greater contact with man and the domestic animals.
The rodents, as it is known, are the main cause of the sustenance of a big group of micro-organisms and parasites in nature, creating the natural focus for diseases, so as to make possible favorable conditions for the infestation of susceptible species, among them, man.
The outbreak of dangerous diseases of bacterial and viral origin has occurred in some zones of the planet, for example, the bubonic plague, by activation of the natural foci, transmitted from one individual to another by fleas. There are still foci in all the continents, with the exception of Australia.
In the last five years, in South America there have been outbreaks of the bubonic plague in Brazil, Bolivia, Ecuador and Peru. In this last country, there have been more than 400 cases in Piura, La Libertad and Lambayeque.
The haemorrhagic fever described in Argentine and Bolivia at the end of the 50's, caused by the Junín and the Machupo viruses respectively, of the Tacribe complex caused a big number of sick persons and of deaths in this zones.
In the case of the Argentine haemorrhagic fever, the main reservoirs (vectors) were the rodents Calomys musculinus and C. laucha, although it has been isolated from other rodents (Akodon azarae, A. obscurus, and Orysomys nigripes). Only in the period from 1965 to 1974, 8728 cases were reported, while in 1967, 300 cases had been registered (Bond, 1977).
The Bolivian Haemorrhagic fever, described for the first time in 1959 in the provinces of Mamor and Iténez, is disseminated by the rodent Calomys callosus. According to the Epidemiologic
Bulletin No. 146 of 1959, in Bolivia there were a total of 1400 cases, with a mortality of 30 to 78%.
It is interesting that in both entities, previous to the occurrence of the disease, there was a perturbation of the environment, especially of the rainfall, and also of the concentration of rodents observed in some crops such as corn, sunflower and other, which, once the crop is over, migrate to nearby lodgings.
In the control of Bolivian haemorrhagic fever, the rat and mice elimination campaign in San Joaquín was considered efficacious (A. P. Buckle et al., 1994).
Leptospirosis, known as "Weil Disease", described at the end of the last century and of world-wide distribution, is caused by about 180 serologic varieties of the interrogans complex, the rodents being the main reservoirs and contaminating swine, bovines and dogs and finally, human beings.
Leptospirosis has a high degree of prevalence in tropical countries due to rainfall, the existence of neutral and alkaline soils and of the adequate temperature for their survival. These conditions propitiate the occurrence of epidemic outbreaks in the zones where the water is contaminated by the urine of infected animals, above all among the workers of rice and sugar cane fields and sewerage or slaughter-houses.
In the last years there have been epidemic outbreaks in different countries of our area: Colombia, Cuba, Brazil, Panama, and, more recently, the outbreak we are referring to, in Nicaragua.
The human leptospirosis epidemics in Nicaragua started on October 18th. in the localities of Achuapa and El Sauce, with 31 probable cases in the first locality and 6 cases in the second. In only one month there were 389 probable cases in Achuapa and 369 in El Sauce. In the beginning, the disease only comprised a few zones in Achuapa. Later on, other localities that showed relatively high indexes of probable cases were Malpaisillo, with 87 cases, León, with 93 cases and Jicaral, with 46 cases.
Other localities had from 1 to 21 cases. Until November 18th, there were a total of 1120 probable cases in Nicaragua .
Before the appearance of the Leptospirosis epidemic in Nicaragua, there was an epidemiologic situation in which there were other diseases of similar clinical symptoms, such as Dengue, Malaria, and Cholera, which contributed to mask the diagnosis and treatment of the disease. That is why 30 days were over before the disease was detected. It was on November 6th. that it was known that it was a Leptospirosis epidemics.
A discriminatory indicative of this entity from other similar ones were 6 dead persons between October 12th. and October 17th. in Achuapa with clinical symptoms in the most cases of headaches, fever, marked osteo-muscular aches, prostration, low blood pressure, shock and respiratory symptoms in the fatal cases, such as dyspnoea, draught, and lung haemorrhage.
On the whole there were 48 probable deaths by Leptospirosis, 8 cases being confirmed by immunohystologic dyeing techniques, in tissues obtained from 10 necropsies. The greatest number of deaths was in the municipalities of Achuapa and El Sauce, of the Department of León, with 6 and 8 deaths respectively and one case in each locality confirmed by the C.D.C. of Atlanta. Another locality that presented 8 probable cases was Dare. The localities or municipalities which presented indexes of probable lethal cases between 4 and 1 were León, San Iced, Jicaral, la Paz Centre, Malpaisillo, Pueblo Nuevo, La Trinidad, Esteem, Juigalpa, Villanueva, Samotillo, Tipitapa, Masaya, Managua and Nandasmo (Table 1).
SUSPECTED DEATHS BY LEPTOSPIROSIS. OCTOBER-NOVEMBER 1995
Number Municipalities No. of deaths Confirmed
1 Achuapa 6 1
2 Sauce 8 1
3 Jicaral 1 1
4 León 4 2
5 La Paz Centro 1 1
6 Malpaisillo 2 1
7 Darío 8 -
8 Pueblo Nuevo 1 -
9 La Trinidad 1 -
10 Estel 2 2
11 San Isidro 2 1
12 Juigalpa 1 -
13 Villa Nueva 3 -
14 Samotillo 1 -
15 Tipitapa 1 -
16 Managua 2 -
17 Masaya 2 -
18 Nandasmo 1 -
Note: Cases were confirmed by histopathology in the C.D.C. of Atlanta
The analysis of the data of the cases by clinical and lethal show a wide distribution of the outbreak of Leptospirosis in Nicaragua
Taking into consideration the exposed problem, the Ministry of Health of Nicaragua decided to carry on a rat and mice elimination campaign in the affected zones and in the zones of risk in order to eliminate the main link of the epidemic chain in the diffusion of the disease (the rodent), together with other ways to environmental health and the adequate treatment in every case.
Among other, the following steps were taken for the control of the rodents:
1. Control of rodents
2. Attention to public health
3. Surveillance of the cases
4. Laboratory
5. Training
6. Management
Because of the preoccupation that existed in relation to the massive rat elimination campaign in such a ample zone of the country with the risk of poisoning of animals and humans, it was decided to use the biological rodenticide "BIORAT", taking into account its being innocuous for persons or animals, its biodegradable nature, and the fact that it is a one-dose product that had been used in the control of the outbreak of the bubonic plague in Peru, in an area of 1041 square kilometers of highly populated territory with positive results, as in other countries of Latin America.
Registration in different Countries.
Country Registration No
Cuba 228/99
Viet-Nam 16/95 FR
El Salvador CAS 95 – 10 –16
Bolivia 004258/95
Honduras 450
Nicaragua Lb – 221 – 95
Guatemala 497 -1
Perú Ms- 018884 – 94
Costa Rica 4130
Rep. Dominicana 1345/99
Líbano 2867/4
Laos 00112/DP – 2000
Mongolia 185
Panamá 48636
Ecuador 18 A- 6919 – SESA - U
Rep Popular China LS - 200159
Angola 578/00
Paraguay 0000020191
Chile P-326-02
Mexico RSCO-URB-RODE-