Sterilization potential of Ascaris lumbricoides eggs in the presence of different disinfectant agents

Introduction: Intestinal parasitic infections represent a public health problem, being responsible for high rates of morbidity and mortality. Ascaris lumbricoides is one of the main parasites prevalent in the community. The A. lumbricoides infection method is oral fecal cicle, in this sense, it is necessary to expand effective methods to prevent the ingestion of eggs, such as sanitation, cleansing habits or even effective methods for the sterilization of eggs. Objective: Evaluate different agents of antisepsis action, with the purpose of find which ones are more efficient in larval mortality inside eggs. Methodology: The parasites were provided by the Federal University of Minas Gerais, which were sectioned, in this way, the recovered eggs were kept in culture bottles. After 40 days, the embryonated eggs were purified and separated in culture bottles, and in each bottle had one different disinfectant products were added, in different concentrations and action time. As control, egg aliquots were maintained by adding distilled water. Using a microscope, it was observed the viability of the larvae inside. To determine the viability of the larvae, distilled water at 40 °C was added, then allowing the visualization of mobility inside the eggs. Results: It was observed that, in the fifteen disinfectant agents tested, only four showed efficacy, at intervals of 24 and 48 hours after exposure to the disinfectant and when undiluted. Conclusion: The data obtained in this study will contribute to the understanding of the epidemiology of this disease, as well as contributing to the development of more effective hygiene programs for the control of this parasitosis.


Introduction
Intestinal parasitosis represent a public health problem, especially in developing countries, being responsible for high morbidity and mortality rates 1-3 .
Among intestinal parasites, Ascaris lumbricoides is considered one of the most prevalent species in the population and one of the main geo-helminths (STH) [4][5][6][7] .
It´s estimated that this parasite is responsible for contaminating approximately 800 million people [8][9][10] . Due to the scope of this disease and the massive number of infected people, it is safe to say that it is a parasitosis neglected by health authorities, especially because the majority of the victims are members of less favored population groups 11-13 . Its occurrence is associated with a lack of hygiene habits, basic sanitation, as well as the geographical area [14][15][16] . Environmental conditions are extremely relevant for infectivity by the parasite. It is known that the eggs eliminated in the host's feces don't have an infection capacity, and in the environment, the larvae inside these eggs, develop and become infectious 17 .
A. lumbricoides infection occurs through the ingestion of viable eggs, present mainly in contaminated water or food [18][19][20] .
Therefore, prophylactic methods to prevent infection consist of ingesting treated water and food asepsis. However, many times the water used by the population is inefficiently treated with chlorine and other products. The A. lumbricoides eggs have a high capacity to survive the treatment of residual water and, as a result, the larvae inside these eggs remain alive, is considered one of the main epidemiological factors of the disease [21][22][23][24][25] . Also, another common practice in Brazil, used as a prophylactic method, consists of washing fruits and vegetables using hypochlorite (sanitary water) and acetic acid (vinegar). However, these practices are also not very  26 , where they used collective A.
lumbricoides eggs in contact with these two agents, to be used in experimental bacteria in animals.
Thus, a factor that could contribute to the prophylaxis of this parasitosis would be the sterilization of eggs in the environment, in water treated by distribution centers, using disinfectant agents, and then filtered to be sent to the population. However, the concentration is not known, nor which agents can exterminate the larvae of A.
lumbricoides inside the eggs 27 .
It is based on this perspective that the present study aimed to evaluate prophylactic methods for disinfection, using different types of disinfectant agents, to ascertain the death of the larvae inside the eggs of this parasite, to make them unviable for the contamination of human beings. The data collected to understand the epidemiology of ascariasis and assist in the development of more effective programs for prophylaxis and its control.

Methodology
The parasites were kindly provided by the Disinfectants were purchased at random as long as they had some action described as germicidal or bactericidal on the product label, at commercial points and identified by codes, to create a trademark for each product.
These products were diluted in distilled water, in the following rules: 25%, 50%, 75% and without dilution. The eggs were kept immersed in disinfectant products for 1, 12, 24, and 48 hours. Revista Conexão Ciência I Vol. 15 I Nº 4 I 2020

Results
When analyzing the viability of the eggs, after exposure to the various products, it was observed that of the 15 disinfectant products tested, only four showed efficacy. Products P3 and P6 had an action within 24 hours of exposure to eggs, and products P11 and P12, within 48 hours (FIGURE 1).

Discussion
In the present study, the results showed that A.
lumbricoides eggs have great resistance. Thereby, it is understood that to eliminate the infectious forms and control the frequency of this parasitosis, it is necessary to find more efficient methods. Revista Conexão Ciência I Vol. 15 I Nº 4 I 2020 lumbricoides eggs. These findings corroborate the data by Massara et al. (2003) 29 . However, other products tested in the present study, also based on pine, had no sterilizing effect. This fact may be related to the disinfectant produced by the manufacturer having a lower concentration of the active principle, which may be involved in the mortality of the larvae.
Other products that have shown efficiency in terms of larval mortality have Sulphonic Acid and Alkibenzene Acid as an active ingredient. These products probably showed efficacy due to their high acidity, which contributed to the larvae inviabilityy inside the eggs.  29 .
In this study, the resistance of A. lumbricoides eggs to different disinfectant agents was demonstrated, in which the larvae remained viable for most of the agents tested. The products that showed efficacy were not diluted, and the time that the eggs of A. lumbricoides were exposed to the product and showed efficacy in larval mortality was much longer than indicated by the manufacturer. This makes the unfeasibility of A.
lumbricoides eggs a problem.
Therefore, new products must be tested to understand the efficacy of these disinfectants as a prophylactic measure for A. lumbricoides eggs, as well as for eggs and cysts of other parasites, since the products routinely for domestic use do not remain for the time necessary for the impracticability of A. lumbricoides eggs as demonstrated in the present study. However, the data obtained in this study may contribute to a better understanding of the epidemiology of these parasites and assist in the development of more effective programs for their control.

Conclusion
A. lumbricoides eggs are extremely resistant and adapted to the adversities of the environment. This is observed because most of the tested products do not have the ability to kill the larva inside these eggs, with this, once in the environment, they can hardly be successfully removed. These results emphasize the need to reevaluate the prophylactic methods already routinely adopted in food hygiene and cleaning in general when the aim is to prevent A. lumbricoides infection, since most procedures are not efficient to combat them. Revista Conexão Ciência I Vol. 15 I Nº 4 I 2020