Hydatid cysts (cystic echinococcosis) are a parasitic disease caused by the larvae of a tapeworm that lives in dogs' intestines. Humans become infected accidentally by swallowing the parasite's eggs in contaminated food or water, or after contact with anything contaminated by dog feces. The cysts grow slowly, most often in the liver and lungs. Imaging and the specialist doctor determine treatment: monitoring, medication, puncture, or surgery. Prevention relies on hygiene, deworming dogs, and not feeding them raw offal.
What Are Hydatid Cysts (Cystic Echinococcosis)?
Hydatid cysts, or cystic echinococcosis, are the cystic form of echinococcosis. They are caused by tapeworm larvae of the genus Echinococcus, specifically the group of species centered on Echinococcus granulosus [1]. It is a zoonotic disease, meaning it passes from animals to humans [1].
The World Health Organization notes that echinococcosis appears in four forms, two of which are the most important for humans: the cystic form and the alveolar form [1]. This article focuses on the cystic form, commonly known as the "hydatid cyst," and mentions the alveolar form briefly where necessary. You can find a reference page on hepatic echinococcosis and hydatid cysts in the directory.
The disease is found worldwide on all continents except Antarctica [1]. It is estimated that more than one million people worldwide are living with the cystic or alveolar form at any given time, and many of them may suffer severe, life-threatening symptoms if left untreated [1].
How Is the Infection Transmitted from Dogs to Humans?
The disease follows a cycle between host animals. Carnivores, led by dogs, are the definitive host, as they carry the adult worm in their intestines [1]. Herbivores and omnivores are the intermediate hosts. They become infected when they swallow eggs in contaminated food or water, and the larvae then develop in their organs [1].
The cycle is completed when a dog eats the organs of an infected animal that contain the larvae [1]. The organization states that the pattern responsible for most human cases occurs mainly in a "dog–sheep–dog" cycle, and other animals such as goats, pigs, cattle, and camels may also be involved [1].
Where Do Humans Fit in This Cycle?
Humans are an "accidental dead-end intermediate host." They become infected the same way sheep do, by swallowing eggs, but they do not contribute to transmitting the infection to dogs [1]. In practice, an infected person does not pass the parasite on to those around them. The real source of risk is eggs that contaminate the environment from the feces of infected dogs.
MedlinePlus notes that parasites in general can be transmitted through contaminated food or water [2]. Therefore, the risk is linked to personal hygiene, washing vegetables, and the source of water, not only to contact with an infected animal.
Where Do Hydatid Cysts Grow, and What Are the Symptoms?
Infection with the cystic form leads to the growth of one or more cysts, most often in the liver and lungs. Less commonly, they may grow in the bones, kidneys, spleen, muscles, or central nervous system [1].
A Silent Period That Can Last Years
Many years may pass without symptoms until the cysts grow large enough to cause clinical signs. However, about half of the patients who receive treatment seek care within a few years of the initial infection [1]. A study in Bulgaria, Romania, and Turkey indicated that the true burden of the disease is not well understood, and that many cases remain without symptoms, proper diagnosis, or treatment [1].
Symptoms by Organ
- Liver: abdominal pain, nausea, and vomiting [1].
- Lung: chronic cough, chest pain, and shortness of breath [1].
- Nonspecific general symptoms: loss of appetite, weight loss, and weakness [1].
- Other symptoms: depend on the location of the cyst and the pressure it exerts on the surrounding tissues [1].
These symptoms are shared with many other diseases, so they do not on their own indicate a hydatid cyst. The alveolar form has a silent incubation period of 5 to 15 years, typically appears as a slow-growing tumor mostly in the liver, and can be fatal if untreated [1]. If you need to understand the organ involved, a page about the Liver is available.
When Should You See a Doctor, and When Should You Go to the Emergency Room?
See a doctor if you have had contact with dogs, sheep, or a rural environment and you have persistent symptoms such as chronic upper abdominal pain, a cough that does not go away, or unexplained weight loss. Also see a doctor if a cyst in the liver or lung is discovered by chance during imaging for another reason, since cysts can be found incidentally on X-rays [1].
Go to the nearest emergency department or call 911 if any of the following occur:
- Sudden, severe abdominal pain.
- Obvious difficulty breathing or severe chest pain.
- Widespread rash or swelling of the face or lips, or a feeling of fainting. These may indicate a severe allergic reaction, which can occur when a cyst ruptures.
- Yellowing of the eyes and skin with fever and abdominal pain.
- Coughing accompanied by the discharge of fluid or membranes.
This list is a warning and is not meant for self-diagnosis. If liver pain remains unexplained, another common cause is viral hepatitis. You can read an explanation in the article Viral Hepatitis: Types, Symptoms and Prevention.
How Is a Hydatid Cyst Diagnosed?
Ultrasound is the preferred method for diagnosing the cystic and alveolar forms in humans. It is often supplemented or confirmed with computed tomography (CT) and/or magnetic resonance imaging (MRI) [1]. Specific antibodies can also be detected through serology blood tests. These support the diagnosis but do not replace imaging [1].
The ultrasound appearance of the cyst is very important, because the choice of treatment is based on it, following an approach specific to each stage [1]. The WHO Informal Working Group on Echinococcosis (WHO-IWGE) established a standardized classification of cysts in 1995, and in 2009 it reached a consensus on diagnosis and treatment [1].
Do not attempt to puncture a cyst suspected of being hydatid or to draw a sample from it outside a treatment plan set by a specialist. The specialist determines how to manage each cyst based on its location and stage.
What Are the Treatment Options for Hydatid Cysts?
The World Health Organization describes treatment of the cystic form as often costly and complex, and it may require extensive surgery and/or prolonged drug therapy [1]. There are four options, chosen based on the cyst's appearance on ultrasound and its stage, as well as the medical infrastructure and staff available [1]:
| Option | What is it? | Notes |
|---|---|---|
| Percutaneous puncture (PAIR) | Puncturing the cyst, draining its contents, injecting a substance, then re-aspirating (Puncture, Aspiration, Injection, Re-aspiration) [1] | Decided by the specialist based on the cyst's stage; not suitable for every cyst. |
| Surgery | Surgical removal of the cyst [1] | The technique varies by organ, and the surgical team determines the most suitable one. |
| Medication | Anti-parasitic drugs [1] | The usual dose and duration are determined by the doctor. Patients should not start or stop the medication on their own. |
| Monitoring (Watch and wait) | Periodic follow-up without immediate intervention [1] | May suit some stages and requires commitment to imaging appointments. |
Medication and Surgery Together
In the alveolar form, the cornerstone remains early diagnosis and radical surgery followed by preventive drug therapy with albendazole, and surgery may be curative if the lesion is limited [1]. Palliative surgery without complete and effective drug treatment, on the other hand, leads to repeated relapses [1]. Do not obtain medication from a pharmacy or from a relative without a prescription. In Jordan, medications are regulated by the Jordan Food and Drug Administration (JFDA), and your doctor decides which one is appropriate for you.
What About Risks and Follow-Up?
The organization notes that the average postoperative mortality in the cystic form is about 2.2%, and that about 6.5% of cases relapse after intervention and need a longer recovery period [1]. These global figures mean that follow-up after treatment is essential. They do not mean that your outcome will necessarily be the same, as the result is affected by the cyst's location and size and your overall health.
For those diagnosed with a lung cyst, a page on lung cyst removal surgery is available. To learn about drug treatment services for parasitic and other infections, you can review infections treatment.
Can Hydatid Cysts Be Prevented?
Yes. The organization describes cystic echinococcosis as a preventable disease, because its cycle depends on pets as definitive and intermediate hosts [1]. Three measures have reduced the disease and prevented its transmission in high-income countries: regularly giving dogs praziquantel to eliminate worms, improving hygiene when slaughtering livestock and properly destroying infected organs, and public education campaigns [1].
Practical Steps for Families
- Deworm dogs regularly: The organization recommends giving dogs praziquantel at least four times a year [1]. A veterinarian determines the appropriate dose.
- Do not feed dogs raw offal: A dog becomes infected by eating the organs of an infected animal [1]. This applies to home slaughter, so make sure to destroy suspected organs properly instead of throwing them to dogs.
- Wash your hands thoroughly: after touching dogs, soil, or the garden, and before eating, and teach children to do the same. MedlinePlus includes hand hygiene and water safety among the sources of prevention for parasitic diseases [2].
- Wash vegetables and fruit thoroughly: especially those grown near areas where dogs roam, and drink safe water. For more on food hygiene, see the article E. coli Infection: Prevention and Treatment.
- Avoid contact with stray dogs: and supervise children when they play with dogs.
What About Vaccination?
MedlinePlus notes that there are no vaccines for parasitic diseases in general, which is why prevention is especially important [2]. The EG95 vaccine for sheep against this parasite is for animals, not humans. It is registered in China and Argentina, and trials in Argentina have demonstrated its benefit [1]. The organization believes that a program combining vaccination of lambs, deworming of dogs, and slaughter of older sheep could eliminate the human disease in less than 10 years [1]. This information is global and does not mean that this vaccine is available in any specific country.
How Do I Find the Right Doctor or Clinic in Jordan?
Care for a hydatid cyst often involves more than one specialty, depending on the cyst's location and the treatment plan. Start with a family physician or a Ministry of Health health center for an initial assessment and appropriate referral. Then search the directory for:
- Infectious diseases: to evaluate parasitic infections and determine drug treatment. You can browse infectious disease doctors in Jordan, or by your governorate: Amman, Irbid, and Zarqa.
- General surgery: when surgical intervention is needed for the liver or elsewhere, through general surgeons in Jordan or general surgery in Amman.
When opening any doctor's or clinic's profile, check the specialty, governorate, and address, the published information about experience and services, and the contact or booking options where the profile provides them. The directory does not assess medical quality or rank doctors, so the choice should depend on what suits your condition.
Useful Questions for Your Appointment
- What stage is the cyst, and what are its size and location according to the tests?
- What options suit my case: monitoring, medication, puncture, or surgery? Why?
- What are the risks of each option, and how will follow-up and periodic imaging be done?
- Should family members be tested, and how should we handle the dogs at home or on the farm?
- What signs require urgent medical review?
Are Hydatid Cysts the Same as Liver Cysts or Hydrocele?
No. Many liver cysts are simple and not parasitic, and a doctor distinguishes them through imaging. For information on this type, there is a page on liver cysts. On the other hand, hydrocele is a completely different condition involving fluid collecting around the testicle, and it has nothing to do with the parasite.
In summary, true hydatid cysts (cystic echinococcosis) result from a parasitic infection that can be prevented through hygiene and by controlling the cycle in dogs and livestock. Any cyst discovered needs assessment by a specialist rather than guesswork, since early diagnosis and a treatment plan suited to the cyst's stage reduce complications. This article is a general overview and does not replace an examination by your doctor.
Frequently asked questions
Can hydatid cyst disease be transmitted from one person to another?
The disease usually does not spread from person to person. A person becomes infected by swallowing the parasite's eggs that come from the feces of infected dogs, through contaminated food, water, or hands. An infected person does not transmit the parasite to dogs. Therefore, prevention focuses on hygiene and controlling the cycle in dogs and livestock.
If I touch a dog, will I get a hydatid cyst?
Simply touching a dog does not mean you will be infected. The risk is that your hands or food become contaminated with eggs from an infected dog's feces and then reach your mouth. Wash your hands with soap and water after handling dogs or soil and before eating, supervise children, and take your dog to a veterinarian for regular deworming.
How long does it take for symptoms to appear after infection?
Many years may pass without symptoms until the cysts grow large enough, while about half of the treated patients seek care within a few years of infection. For this reason, many cysts are discovered by chance during imaging, and you should see a doctor for persistent symptoms in the liver or lungs.
Which test detects hydatid cysts?
Ultrasound is the preferred method and is often supplemented by CT or MRI when needed. Serology blood tests may support the diagnosis by detecting specific antibodies. The doctor interprets the results and determines the cyst's stage before choosing treatment.
Does every hydatid cyst require surgery?
No. There are four options: percutaneous puncture (PAIR), surgery, medication, and monitoring. The specialist chooses among them based on the cyst's appearance and stage, the patient's condition, and the available resources. Do not start or stop any medication on your own, and ask your doctor about the follow-up plan.
How can I protect my family from hydatid cysts if we have a dog or sheep?
Give the dog deworming medication under the supervision of a veterinarian. The World Health Organization recommends at least four times a year. Do not feed it raw offal, and destroy suspected organs properly. Wash your hands and garden vegetables well, drink safe water, and teach children these habits.
Sources and references
- Echinococcosis — World Health Organization. Accessed: 2026-10-26.
- Parasitic Diseases: MedlinePlus — MedlinePlus — U.S. National Library of Medicine. Accessed: 2026-10-26.