Cystic hydatid disease (CHD) is the infection with the larvae of Echinococcus granulosus and a common cause of lung and liver disease worldwide. In the life cycle of this zoonotic cestode, dogs carry in their small intestine the adult form of the parasite or tapeworm, acquired by eating infected offal from the intermediate herbivorous hosts. Humans enter the cycle accidentally by ingesting infective tapeworm eggs, and children being more exposed to infection through close interaction with dogs (Moro & Schantz 2009). The Central Highlands of Peru, a region within altitudes between 3000 and 4500 m, is hyperendemic for CHD (McManus et al. 2003): the prevalence in the general population by chest X-ray or liver ultrasound can reach 5.5% (Gavidia et al. 2008).
Cystic hydatid disease is deeply rooted on poverty and inadequate practices; there is, however, only scarce literature on disease-related knowledge, attitudes and practices. In rural areas of Peru, ignorance of the mechanisms of infection and transmission is clearly associated with the persistence of CHD (Moro et al. 2005). We evaluated basic knowledge on disease origin and a few associated factors in caregivers of children who received treatment because of CHD in a reference center in Lima, Peru.
The study was conducted at the Instituto Nacional de Salud del Niño (INSN), the largest paediatric hospital in Peru. After appropriate approvals, we reviewed the medical records of patients with CHD seen between the years 2001–2008 and attempted to contact the adult relatives who were responsible for the care of patients at that time. Those contacted were asked to answer a telephone survey, which had been initially revised by two experts in hydatid disease and then by a methodological committee before its application. This survey consisted of seven multiple-choice questions on the name of the disease, parasite life cycle and ways of infection, prevention, complications and treatment. Data were entered into an Excel spreadsheet (Microsoft, Seattle, WA, USA) and imported into Stata 10 for Windows software (Stata Corp, College Station, TX, USA) for analysis. Univariate analysis was followed by evaluation of associations between categorical variables using either chi square test or Fisher’s exact test.
We accessed the records of 148 patients. Eighty-two (55%) were men; the average age was 8.13 years (range 2–15 years). The vast majority had lung or liver involvement [lung = 90 (60.8%), liver = 66 (44.6%), both organs = 12 (8.1%)]. Four had disease outside lung or liver only: one had a cyst in the posterior mediastinum, one in the spine (intramedullary cyst), one in the lymphatic vessels and one in the diaphragmatic surface. One of the cases with lung CHD also had splenic involvement, and from those with lung and liver disease, one had additional splenic involvement, and another had additional brain involvement. The treatment was surgical in 141 (95%) of the cases.
Seventy-six charts had a phone number registered. Only one third of these lines (26/76, 34%) were operative, leaving an eligible population of 26 cases. Compared to the entire hospital case series, these patients had similar age (average age 7.92 years, range 3–15, P = 0.70) and were men in similar proportions (14, 54%). All contacted cases had lung or liver compromise (lung = 17, 65%, liver = 13, 50%, both organs = 4, 15%). Twenty-five of the 26 patients had surgery. The remaining patient had medical treatment initially and then underwent surgery because of a new cyst at a different site 8 years after the first diagnosis. Twenty-two (84.62%) participants had dogs at the time of the children’s diagnosis. Most of them were living in Lima (Figure 1).
Of the 26 contacted families, all agreed to be interviewed and had a responsible relative co-operating with the study. The responsible relatives were mostly women (23, 88%), in most cases the patient’s mother (18, 69%). Three respondents were the fathers, and 5 (19%) had another relationship to the child. Their education level was generally high: 11 (42%) had university education, 8 (31%) had completed high school, 6 (23%) had completed primary school and one was illiterate.
The survey and obtained responses are described in Table 1. Ten (40%) individuals failed to correctly respond at least three of the seven questions; only 5 (20%) answered all seven questions correctly. As expected (Apt et al. 2000; Cabrera et al. 2005), a higher education degree or completed secondary school was associated with correctly answering questions related to complications of the disease when compared with having completed primary school only (P = 0.002 and P = 0.041, respectively).
|1. Can you tell the name of your child’s disease?|
|a. Hydatid cyst or hydatid pulmonary/hepatic disease||26 (100)|
|b. Pulmonary/hepatic tumour||0|
|c. Water bag||0|
|d. I do not know||0|
|2. Which of the following animals is the source of infection for this disease?|
|a. Dog||20 (76.93)|
|b. Cat/pig||6 (23.07)|
|3. Which one of these transmits the infection to humans?|
|a. Dog flea/dog scabies||12 (46.16)|
|b. Dog’s worm||9 (34.62)|
|c. Sheep’s cyst||5 (19.23)|
|4. Of these alternatives, which is the correct mode of transmission?|
|a. Playing with dogs||10 (38.46)|
|b. Eating the eggs from dog’s faeces||9 (34.62)|
|c. Eating the viscera with cysts/being in contact with infected people||7 (26.92)|
|5. Which is the best way to be protected against this disease?|
|a. By washing hands and eating cooked food||17 (65.38)|
|b. By not feeding the animals with raw viscera or by deworming the animals||8 (30.77)|
|c. By using facial masks||1 (3.85)|
|6. How people can be cured from this disease?|
|a. With surgery||25 (96.15)|
|b. With pills only||1 (3.85)|
|c. With vaccination/Do not need any treatment||0|
|7. Do you know what could have happened to your child if he/she did not undergo surgery?|
|a. Progressive growth of the cyst until rupture||20 (76.93)|
|b. Spontaneous remission/Malignant transformation||5 (19.23)|
|c. New cysts in other parts of the body||1 (3.85)|
Although 20 participants (76%) correctly identified the dog as part of the cycle, most (17, 65%) incorrectly identified the etiologic agent and mode of transmission. This is different from studies where family members of patients with CHD identified rabies as the only disease humans can get from dogs (Hemachander et al. 2008), but similar to studies revealing a lack of knowledge about the life cycle of E. granulosus (Kachani et al. 2003; Nasrieh et al. 2003).
Despite this being a telephone survey in a small population, several areas of poor knowledge were demonstrated. This is even more significant as most of the potential biases were oriented towards increased knowledge: a study population composed of close relatives of patients who had surgery for CHD, higher socioeconomic status (having a telephone line/greater access to information, most likely still living in Lima). Worse the aspect in which most of the interviewed lacked knowledge was precisely the life cycle of the E. granulosus, where unhealthy practices contribute to maintain the endemicity of disease (Cabrera et al. 2005). Educational measures should be an obligatory part of hydatid control. Our findings highlight the need for baseline determination of the level of information in different subpopulations for properly targeting educational measures as part of larger, more comprehensive CHD control programs.