A Case of spp. in a Woman from an Urban-Marginal Sector of Ecuador

Background

Protozoa and helminths (enteroparasites) are very prevalent and persistent worldwide. It is estimated that 3.5 billion people around the world are affected, constituting a serious public health problem due to the epidemiological triangle of parasitic diseases, that is, the relationship between the condition of the host, the parasite, and the environment [1,2]. Helminths are highly prevalent in developing countries, and their frequency is an indicator of socioeconomic and health deficiency in a region. Parasite occurrence is prevalent among hosts exposed to poor basic sanitary conditions and with low levels of education (schooling) and inadequate hygiene habits, which allows the appearance of parasites, affecting the health of local populations [3]. Parasites can cause various gastrointestinal pathologies, malnutrition, cognitive and physiological delays, and even death, independent of age [2].

In 1991, Dr. Francisco Tirado Santamaría reported the first cases of Urbanorum spp. in fecal samples of patients treated in Barrancabermeja Health Center (Colombia) and described it as a risk of public health [4]. Urbanorum spp. are observed as rounded structures between 80 and 100 µm in diameter; when stained with Lugol’s solution, this helminth exhibits light yellow content with a double outer membrane that presents pores through which hyaline structures emerge from its interior, similar to pseudopods, constituting their mode of locomotion [4,5]. Reproduction occurs by binary division, and thus, Urbanorum spp., apparently does belong to the phylum Sarcomastigophora, are considered an amoeboid protozoan, with reproduction by endodiogenesis, and so far, the life cycle in humans is not known [6,7].

Similar to other intestinal parasites, the transmission of Urbanorum spp. is associated with lack of personal hygiene and water, soil, and food contaminated by the protozoan and is the cause of acute diarrheal syndrome, which is characterized by fever, vomiting, diarrheal stools, colic, dyspepsia, and liquid stool samples without blood, mucus, or leukocytes, and with acidic pH. These symptoms are due to the attack of this presumed parasite in the large intestine of the host. [2,6]. For the treatment of infected patients, metronidazole and secnidazole are recommended [7,8].

Ecuador has high rates of intestinal parasites [9,10], and this report presents a case of natural infection by Urbanorum spp. Therefore, health professionals and officials must provide information to the population to guide them in prevention.

This case report was part of the FCI-029 Project (Fund Competitive of Research) approved and was financed by the University of Guayaquil (Ecuador), called: “Ecoepidemiology of neglected intestinal helminthiasis in urban-marginal and rural areas of the Guayas province”.

Case Report

A thin, 40-year-old woman who weighed between 57 and 60 kg was a resident of the urban-marginal sector of the “Balerio Estacio” Cooperative of the city of Guayaquil, Ecuador; she had a history of diarrhea, low body weight, abdominal discomfort, and fever of 2 days of evolution. She consulted researchers from the FCI-029 Project of the University of Guayaquil (“Ecoepidemiology of Neglected Intestinal Helminthiases in Urban-Marginal and Rural Areas of the Province of Guayas,” on November 24, 2022. That same day the patient was seen in the Private Ecomedical Center, the symptoms were considered, and the infection was confirmed with the results obtained from the laboratory.

The physical evaluation carried out showed that the ocular and oral mucosa, cardiac and pulmonary auscultation, and abdominal palpation and percussion were normal.

The place where the patient resides did not have adequate sanitation, which had a large epidemiological impact, and was a research site of the aforementioned project. Informed consent was requested from the patient before a sample was obtained. The method for obtaining the sample was explained to the patient, who was provided a sterile container. Fecal samples were transported on the day of collection in refrigerated boxes (4–8°C) to the “Pazmiño” Clinical and Microbiological Laboratory in the city of Milagro.

The samples obtained were semi-liquid, common to diarrhea. Later, they were analyzed using coproparasitic methods: direct parasitological and sedimentation with centrifugation using saline solution. The sample was stained with Lugol’s solution and examined the same day using 10× and 40× objectives.

The analyzed sample lacked red blood cells, leukocytes, and mucus, but contained a round structure and several filaments, similar to those described by Rodrigues and Gonçalves (2022) and Sousa and Alves (2018) [2,6] (Figure 1). In addition, the microscopic analysis of the presumed parasite was indicative of Urbanorum spp., later confirmed by an expert from the University of the Americas (UDLA) of Ecuador, causing concern because it was another case report of this presumed parasite in Ecuador.

The patient was treated with metronidazole administered in doses of 500–750 mg PO every 8 hours for 10 days. Fourteen days after treatment, the team from Project FCI-029 of the University of Guayaquil reported that the patient’s health had improved.

The blood tests performed presented normal values. In addition, a differential diagnosis was made in a private laboratory through fecal parasitology and stool cultures of Amebiasis, Giardiasis, Cystoisosporiasis, Colibacillosis, and Salmonellosis, but none were registered.

A limitation of the present report is that the patient could not be followed up after treatment since she did not repeat the parasitological tests after she felt better. However, the identification of Urbanorum spp. was very important.

Discussion

The environmental conditions in Ecuador are favorable for the appearance of cases of intestinal parasites. In Latin America, Urbanorum spp. infection has also been reported in Colombia, Peru, Ecuador, Brazil, and Mexico [5,6,11,12]. The structure of Urbanorum spp. in this report had the same morphological characteristics as those reported by other authors [2,13,14], which suggests the presence of natural infection of this presumed protozoan in Ecuador.

In South America, Urbanorum spp., like other human intestinal parasites, are acquired through fecal-oral infection by ingesting food or water containing parasite cysts [4].

Tirado Santamaría carried out several studies that serve as an epidemiological record of this infectious agent in Colombia. In 1991, he observed Urbanorum spp. in samples of symptomatic patients treated at the Barrancabermeja Health Center [5]. Three years later, Urbanorum spp. was found in 16.6% of 283 samples analyzed, and in 13.98% of 143 samples in 1996. Between 1997 and 1998, of 14 000 fecal samples, 1400 contained the presumed parasite. In Barrancabermeja, in 2006, of 500 fecal samples of from school children, a prevalence of 10% was determined. One year later, in Piedecuesta-Santander, 200 samples from school-age children were analyzed, of which 5% contained the presumed parasite [4,5].

In Peru, during 2006, of a total of 96 children 3–14 years of age, 20.8% were infected with Urbanorum spp. [15]. That same year, a 67-year-old woman with abdominal pain and dyspepsia for 9 months from San Juan de Lurigancho (Lima) consulted at the Aurelio Díaz Hospital, and was diagnosed with infection with Urbanorum spp. and other protozoa [5].

In Ecuador in 2016, in a study on the prevalence of protozoa and helminths in 3 different regions of Ecuador, out of a total of 295 fecal samples, various types of parasites were identified. Furthermore, the presence of Urbanorum spp. was reported in the Costa region for the first time, with a prevalence rate of 1.16% [12]. Two years later, this infectious agent was identified in the city of Milagro. Of a total of 225 people studied, between 2 and 86 years old, 4 were infected by Urbanorum spp. (1.77%), but they were asymptomatic; this was presented at the 14th International Congress of Parasitology 2018 in Daegu-Korea [16]. Ayol (2022) identified the protozoan in a child from the rural parish of Mariscal Sucre in the city of Milagro [17].

In Brazil, the first report of Urbanorum spp. occurred in 2017 in a 41-year-old woman who weighed 55–60 kg and resided in the city of Buriti in Maranhão. This rural area does not have basic sanitation or access to drinking water. She had abdominal cramps and fever and was diagnosed with acute diarrhea [6]. A year later, the second case was reported, in the city of Livramento, Rio Grande do Sul, in a 72-year-old patient with Sjögren’s syndrome, but he did not have symptoms. In the same year, 2 other patients were diagnosed with Urbanorum spp. [18]. In that same year, in the city of Imperatriz – Ma, of 5428 parasitological examinations of samples from individuals 28–77 years old, 25 (0.46%) were positive. In 2018, Leão et al analyzed a total of 5786 stool samples, and 84 (1.45%) had morphological characteristics compatible with Urbanorum spp. [19,20]. In 2019, in São José dos Pinhais-Paraná, infection occurred in a 56-year-old male diabetic patient who used metformin and consulted the doctor mainly for abdominal colic [18].

In a study carried out in 2020 in cities of the Vale do Paraíba metropolitan region, of a total of 2777 samples analyzed using the Hoffman, Pons, and Janner technique, 252 samples (9.07%) were positive for Urbanorum spp. [2].

In 2019 in Veracruz (Mexico), Bonilla et al found the first case of Urbanorum spp, using the direct coproparasitic method. The patient was a 49-year-old woman with nausea, headache, flatulence, substantial abdominal distention, and colicky pain, without fever or vomiting. Her stools were brown, soft, and bloodless, with mucus. Three days after onset, she developed hyporexia, a poor general condition, nausea, abdominal distention, slight dehydration of the oral mucosa, an increase in the number of evacuations from 4 to 5 per 24 hours, and prostration [13].

Although previous studies have performed several different parasitological techniques, the techniques used in the present study (direct method and sedimentation method) effectively identified Urbanorum spp. The environmental, sanitary, sociocultural, and economic conditions of an area influence the epidemiology of this presumed parasite [15]; therefore, it can persist in different environments, for example, rural areas [6], urban areas [4,5] and urban-marginal areas, as in the present study, creating a high public health risk.

The reports of Urbanorum spp. have sparked debates in the scientific community. According to Rivero, the hyaline structures identified by Professor Tirado are related to connective tissue adipose cells, which, when broken, release a series of filaments that can temporarily exhibit ineffective movement, similar to the emission of pseudopods from macrophages [21]. In addition, Silva-Diaz stated that studies are needed to verify the biological status of Urbanorum spp. and contribute to taxonomy, and it is necessary to perform parasitological cultures, molecular analysis, and electron microscopy. Further scientific evidence and randomized controlled trials are needed to determine the cause-effect relationship between the infectious agent and the host [8].

This study was based on the identification of morphological characteristics of Urbanorum spp; however, more studies are needed to confirm the parasitic etiology. Likewise, in light of this other case of this presumed parasite in Ecuador and another case in South America, and because of the favorable conditions for development, it is likely that cases will occur in other places, generating a serious public health problem because acute diarrheal syndrome can trigger malnutrition and dehydration, especially in children and populations with nutritional deficiencies; therefore, prevention is of the utmost importance [2].

Despite the limitations of this study, control and prevention of Urbanorum spp. should be implemented, and risks and treatment methods should be explored. Our study allows comparison with other cases to estimate the prevalence and identify cases with diarrheal symptoms.

Our report presents relevant points regarding Urbanorum spp. and encourages rapid and timely diagnosis. Future studies are recommended to identify unknown cases of Urbanorum spp. in other regions of Ecuador. Finally, it is necessary to create a national registry for this presumed protozoan of public health importance, which could serve as a national registry and as a reference for new case reports.

Conclusions

In this article we report another case of Urbanorum spp. in Ecuador, which could be a risk to public health. Further studies are recommended to confirm its identity as a protozoan and its pathogenic capacity. Therefore, it is necessary to raise awareness about this presumed emerging parasite. In addition, more research is necessary to know its life cycle and epidemiological characteristics.