Alveolar echinococcosis is a rare parasitic infection that behaves like a slow‑growing tumor in the liver. People with alveolar echinococcosis may notice tiredness, belly discomfort on the right side, or weight loss, and doctors may find liver enlargement or abnormal scans. It usually progresses over years if untreated and can be serious or life‑threatening, but earlier diagnosis improves outcomes. Alveolar echinococcosis is most often seen in adults in areas where the parasite is common, and exposure risks vary by region. Treatment usually involves long‑term antiparasitic medicine and, when possible, surgery to remove affected tissue.
Overview
Alveolar echinococcosisSymptoms
Early symptoms of alveolar echinococcosis are often silent for years. Later, people may notice right upper belly pain, fatigue, weight loss, nausea, or jaundice. Severe cases can block bile flow, cause liver failure, or spread to the lungs or brain.
Outlook and prognosis
Many living with alveolar echinococcosis do well when it’s found early and treated long term with appropriate medicines and, when possible, surgery. Regular imaging and blood tests help track response and catch regrowth. Delayed diagnosis can mean more extensive treatment and closer follow-up.
Causes and risk factors
Alveolar echinococcosis starts after swallowing Echinococcus eggs from fox or dog feces contaminating food, water, or hands. Risk increases with time in endemic rural areas, dog/fox contact, foraging or gardening, poor hand hygiene; immunosuppression worsens disease; no confirmed genetic risk.
Genetic influences
Genetics plays a limited role in alveolar echinococcosis, which is an infectious disease, not an inherited one. Variations in immune-system genes may influence risk, severity, and response to infection. Family members don’t inherit the disease, but shared environments can affect exposure.
Diagnosis
Doctors suspect alveolar echinococcosis from liver imaging, such as ultrasound, CT, or MRI, showing tumor-like lesions. Blood antibody tests support the diagnosis, and sometimes a biopsy confirms it. Exposure history helps guide the diagnosis of alveolar echinococcosis.
Treatment and drugs
Treatment for alveolar echinococcosis typically combines long-term antiparasitic medicine (most often albendazole) with surgery when safe and feasible. Care teams also use imaging and blood tests to track response. In advanced cases, liver transplantation or interventional radiology may be considered.
Symptoms
Alveolar echinococcosis mostly affects the liver and tends to creep in slowly, so many people feel well for years. Early symptoms of alveolar echinococcosis are often subtle—dull aches under the right ribs, tiredness, or feeling full after small meals. Symptoms vary from person to person and can change over time. As the growth in the liver enlarges or blocks bile flow, yellowing of the skin and eyes, itching, nausea, or intermittent fevers can appear.
A dull ache or pressure under the right ribs is common as the liver is affected. It may come and go and can feel worse after eating or bending.
Ongoing tiredness not relieved by rest can develop. Daily tasks may take more energy than usual.
Gradual weight loss can happen even without dieting. It often pairs with low appetite or nausea.
Mild nausea, bloating, or a reduced desire to eat can show up. This may be more noticeable after fatty meals.
How people usually first notice Alveolar echinococcosis?
People usually first notice alveolar echinococcosis months to years after infection, when vague symptoms like upper abdominal discomfort, fatigue, unexplained weight loss, or mild jaundice start to build. Doctors often pick it up incidentally on an ultrasound or CT scan done for “liver cysts” or abnormal liver tests, where the lesion can mimic a slow-growing liver tumor. In areas where the parasite is rare, the first signs of alveolar echinococcosis are frequently missed until the mass enlarges or spreads to nearby bile ducts or, less often, the lungs or brain.
Types of Alveolar echinococcosis
Alveolar echinococcosis is a parasitic disease that behaves more like a slow-growing tumor in the liver, and sometimes spreads to nearby structures or distant organs. Clinicians often describe the disease pattern by where it is and how far it has spread, which helps predict symptoms and guide treatment. Symptoms don’t always look the same for everyone. When people search for types of alveolar echinococcosis, they’re usually asking about disease patterns rather than different genetic variants of the parasite.
Liver‑limited disease
Symptoms often build slowly with dull right‑upper belly discomfort, fatigue, or mild weight loss. Blood tests may show liver irritation, but many feel well for years.
Bile duct involvement
Pain can be sharper with jaundice, dark urine, pale stools, and itching when cyst-like tissue blocks bile flow. Doctors may see enlarged bile ducts and lab signs of cholestasis.
Vascular invasion
When growth narrows liver blood vessels, people can develop swelling of the belly (ascites) or leg edema and feel more easily winded. Imaging may show reduced blood flow or portal hypertension.
Adjacent spread
The lesion can extend to nearby organs like the diaphragm or adrenal gland, causing back or flank pain and sometimes fullness after small meals. Local pressure effects tend to drive symptoms.
Distant metastasis
Lungs or brain can be involved in advanced cases, leading to cough or shortness of breath, or headaches and neurologic changes. Early symptoms of alveolar echinococcosis outside the liver can be subtle and easy to miss.
Post‑treatment state
After surgery or long-term antiparasitic therapy, many feel better but may have fatigue or digestive changes from residual liver scarring. Follow‑up scans and blood tests track whether disease is inactive or controlled.
What genetics can tell you about symptoms
Certain genetic differences in immune genes, like HLA and TLR variants, can weaken early parasite recognition, which may lead to larger liver lesions, faster growth, and more symptoms such as pain or fatigue. Variants affecting fibrosis pathways (e.g., TGF-β signaling) can drive scar tissue, causing biliary blockage and jaundice.
Causes and risk factors
Alveolar echinococcosis is caused by swallowing tiny eggs from a fox tapeworm (Echinococcus multilocularis).
The eggs can be on soil, water, pet fur, or unwashed produce contaminated by droppings from foxes, coyotes, or dogs.
Risk factors for alveolar echinococcosis include living in areas where the parasite is found, including parts of Europe and North America.
Outdoor work or hobbies and dogs that roam and hunt add exposure, and weakened immunity can make disease more severe.
Some risks are modifiable (things you can change), others are non-modifiable (things you can’t).
Environmental and biological risk factors
Alveolar echinococcosis is a parasitic infection that mainly affects the liver and can behave a bit like a slow-growing tumor. Doctors often group risks into internal (biological) and external (environmental). Here we focus on the exposures in your surroundings and body-based factors that raise the odds of contact and illness. Understanding these risks can help you seek care early if you notice early symptoms of alveolar echinococcosis.
People living in or traveling to certain regions where the parasite circulates face higher exposure. These include parts of Europe, Asia, and North America, including Alaska.
Red foxes and coyotes carry the parasite and shed microscopic eggs in their droppings. When these animals range near homes, farms, or parks, eggs can contaminate soil and surfaces. This environmental spread increases the chance of alveolar echinococcosis in nearby communities.
Dogs, and less often cats, can become infected after catching small rodents in endemic areas. Infected pets can bring eggs into yards and homes through feces or contaminated fur. This can raise household exposure.
Voles and other small field rodents help the parasite’s cycle continue. Landscapes with many rodents can support higher egg contamination in the environment.
Genetic risk factors
For alveolar echinococcosis, there is no single inherited cause; it results from infection rather than a gene change passed through families. Some people may carry small differences in immune-response genes that affect how strongly their body controls the parasite and how the illness unfolds. Carrying certain risks doesn’t automatically lead to alveolar echinococcosis, and there is no routine genetic test to predict it. Current studies show associations, not certainties, and they are not yet used to guide screening.
No single-gene cause: Alveolar echinococcosis arises from an infection, not from an inherited mutation. Having a relative with the condition does not mean it is genetic or that it will run in your family.
Immune-response genes: Common gene differences that tune immune signals may influence who becomes infected or develops more severe disease. These links are research findings and are not used in everyday care.
Tissue-type variation: Variants in tissue-type genes that help the immune system recognize invaders have been tied to differing susceptibility in small studies. Findings are inconsistent and have not led to testing or prevention strategies.
Inherited immune defects: Rare, inherited immune deficiencies can lower the body’s ability to control parasitic infections and may worsen the course. Doctors may look for these conditions when disease is unusually aggressive or persistent.
Family clustering: When more than one family member is affected, patterns usually reflect non-genetic factors rather than heredity. Questions about genetic risk factors for alveolar echinococcosis are common, but most families do not have a hereditary risk.
Genetic testing limits: There is no validated genetic test to predict who will get alveolar echinococcosis or how it will progress. If you’re unsure about your risks, a doctor can provide clarity.
Lifestyle risk factors
Alveolar echinococcosis is acquired by ingesting microscopic eggs shed by infected wild canids; day-to-day habits can raise or lower exposure. The lifestyle risk factors for Alveolar echinococcosis center on how you handle food, water, pets, and outdoor activities in endemic areas. Understanding how lifestyle affects Alveolar echinococcosis can guide simple behavior changes to reduce risk.
Eating unwashed wild berries, herbs, or mushrooms can carry parasite eggs from fox-contaminated environments. Washing and cooking foraged produce reduces the chance of ingesting eggs.
Petting or cleaning dogs or cats that roam and hunt rodents can transfer eggs to hands. Handwashing after handling pets and before eating cuts transmission risk.
Allowing dogs or cats to hunt rodents increases their chance of carrying eggs on fur. Keeping pets leashed and preventing rodent hunting lowers household exposure.
Skipping regular deworming lets intestinal tapeworms persist in dogs. Vet-directed praziquantel deworming schedules reduce shedding risk.
Risk prevention
Alveolar echinococcosis spreads when parasite eggs from wildlife or infected pets get into the mouth, often via soil, fur, or unwashed food. Because early symptoms of alveolar echinococcosis can be vague, prevention matters in day-to-day routines. Prevention is about lowering risk, not eliminating it completely. The steps below focus on safer food handling, pet care, and reducing contact with contaminated soil or animal waste.
Wash hands with soap and water after gardening, handling soil, or picking up pet waste. Clean hands before eating or preparing food to avoid swallowing parasite eggs.
Rinse or scrub wild-picked berries, mushrooms, and herbs under running water. Cooking is safest when you are unsure about cleanliness.
Ask your veterinarian about regular deworming for dogs and outdoor cats, especially if they hunt rodents. Follow the advised product and schedule closely.
Keep dogs on a leash and consider keeping cats indoors. Reducing rodent hunting lowers the chance pets bring the parasite home.
Transmission
Alveolar echinococcosis is picked up by swallowing microscopic tapeworm eggs shed in the feces of foxes and dogs, usually through contact with contaminated soil, water, or food. This can happen while gardening or handling soil, picking unwashed wild berries or mushrooms, or touching a dog or cat that has rolled in areas with fox droppings. That’s how alveolar echinococcosis is transmitted; it does not spread through casual contact, coughing, or from one person to another. Alveolar echinococcosis is not highly contagious in everyday life—the risk is tied to environmental exposure in places where the parasite is present.
When to test your genes
Consider genetic testing if you have a strong family history of immune disorders, unexplained liver lesions, or severe, recurrent infections that raise concern for impaired parasite defense. It’s most useful to guide care only alongside imaging, serology, and specialist input. Ask your clinician if testing immune-related genes could tailor your monitoring or treatment.
Diagnosis
Many people learn about alveolar echinococcosis after a scan for ongoing stomach discomfort or an unexpected liver finding. Doctors usually begin with a careful review of symptoms and basic tests, then use imaging and bloodwork to narrow the possibilities. Understanding how alveolar echinococcosis is diagnosed can help you know what to expect. In most cases, several steps are combined to confirm the cause and plan treatment.
Your doctor asks about where you’ve lived or traveled, outdoor activities, and contact with dogs or wild canids. They also review symptoms such as abdominal pain, fatigue, or weight changes, and how long they’ve been present.
A focused exam checks for liver tenderness or enlargement. Blood tests look at liver function and inflammation; results can be normal early on.
Ultrasound often spots an irregular mass in the liver that may contain small pockets and calcifications. It’s a quick, noninvasive way to see if the liver architecture looks suspicious for alveolar echinococcosis.
Contrast-enhanced scans show the full outline of the lesion and whether bile ducts or blood vessels are involved. These images help tell parasitic disease from cancers and guide treatment planning.
Stages of Alveolar echinococcosis
Knowing the stage helps guide treatment and follow-up. In alveolar echinococcosis, doctors look at how far the parasite-related liver lesion has grown, whether it reaches nearby structures, and if it has spread to other organs. Different tests may be suggested to help map this out, including ultrasound, CT/MRI, and special blood tests. Early symptoms of alveolar echinococcosis are often subtle, so imaging usually does most of the staging work.
Early localized
A small lesion is limited to part of the liver. With alveolar echinococcosis, many feel well at this point or have vague upper‑abdominal discomfort. It’s often found by chance during an ultrasound or scan for another issue.
Bile duct or vessels
The lesion starts to block bile ducts or press on liver blood vessels. This can lead to jaundice, abdominal pain, or abnormal liver tests. Care aims to relieve blockages and control further growth.
Locally advanced liver
Several liver areas are involved but there’s no spread beyond the liver. Fatigue, weight loss, or pain under the right ribs may appear. Treatment often combines long-term antiparasitic medicine with procedures or surgery when possible.
Nearby organ extension
Growth reaches nearby structures such as the diaphragm, gallbladder, or regional lymph nodes without distant spread. People may notice worsening pain or digestive upset. Teams plan targeted procedures and continued medicine to contain disease.
Distant spread
The parasite has reached other organs, commonly the lungs or, rarely, the brain. Symptoms depend on the organ involved, and alveolar echinococcosis care focuses on long-term control. Medicines continue and specific procedures address complications as they arise.
Outlook and prognosis
Looking ahead can feel daunting, but most people want to know what life with alveolar echinococcosis may look like over time. Without treatment, the infection can keep growing in the liver and sometimes spread to the lungs, brain, or other organs, which can be life‑threatening over years. With modern care, especially long‑term antiparasitic medicine and surgery when feasible, survival has improved greatly. Doctors call this the prognosis—a medical word for likely outcomes.
Outcomes vary by how early alveolar echinococcosis is found, where it has spread, and whether complete surgical removal is possible. When surgery fully clears the lesions and medicine continues as advised, many people return to regular routines with close follow‑up. If surgery isn’t possible, continuous medication can often control growth and prevent complications, turning it into a chronic but manageable condition. Early symptoms of alveolar echinococcosis can be subtle—such as vague abdominal discomfort, fatigue, or mild weight loss—so screening after exposure in endemic areas or after high‑risk activities matters.
Mortality is highest when the disease is diagnosed late or treatment is interrupted, but long‑term therapy can significantly reduce this risk. Regular imaging and liver function checks help catch changes before they cause major problems. Knowing what to expect can ease some of the worry. Talk with your doctor about what your personal outlook might look like.
Long-term effects
Living with alveolar echinococcosis can affect day-to-day energy, appetite, and comfort, especially as the liver works harder over time. Long-term effects vary widely, and depend on how early the condition is found and how well treatment keeps it under control. Early symptoms of alveolar echinococcosis can be subtle, so some people only notice issues years after infection. With modern care, many continue with daily life, but the condition may still cause ongoing liver and bile duct problems.
The parasitic growth can slowly replace healthy liver tissue and scar it. Over years, this can lead to reduced liver function and, in some, liver failure.
Growing lesions can squeeze the bile ducts, causing jaundice, dark urine, pale stools, and itching. Repeated blockage can damage the liver further.
Scarring can raise pressure in the main vein leading to the liver, which can enlarge the spleen and cause belly fluid build-up. In severe cases, swollen veins in the esophagus can bleed.
Blocked bile flow can invite infections of the bile ducts with fever and chills. These bouts (cholangitis) may lead to hospital stays and antibiotics.
How is it to live with Alveolar echinococcosis?
Living with alveolar echinococcosis can feel uncertain because the illness often progresses slowly and silently, then demands long-term treatment once it’s found. Daily life may include regular imaging and blood tests, years of antiparasitic medication with possible side effects like stomach upset or fatigue, and, for some, surgery and recovery planning. Work, travel, and family routines may need extra scheduling around appointments and medication timing, and avoiding certain activities after liver procedures may be advised. People close to you often take on supportive roles—helping with transport, meals, or reminders—and benefit from clear updates and shared plans so everyone feels prepared rather than overwhelmed.
Treatment and drugs
Treatment for alveolar echinococcosis focuses on removing as much of the parasitic growth as possible and controlling any remaining disease long term. When feasible, surgeons aim to fully remove the affected liver area; if that’s not possible, long-term antiparasitic medication such as albendazole is used to slow or stop growth and prevent spread. Medicines that ease symptoms are called supportive care, and this can include pain control, treatment for bile duct blockage, and nutritional support if the liver is under strain. Treatment plans often combine several approaches, and regular imaging and blood tests help your team track response and adjust the plan over time. Finding the right therapy can take some time, so your doctor can help weigh the pros and cons of each option.
Non-drug treatment
Care for alveolar echinococcosis often includes procedures and supportive therapies that ease symptoms, protect the liver, and help you stay active day to day. Alongside medicines, non-drug therapies can manage blockages, treat infections, and make surgery safer when it’s needed. Regular follow-up also helps spot changes early, including early symptoms of alveolar echinococcosis that can be easy to miss. These options aim to control complications, support nutrition and energy, and maintain quality of life.
Surgeons remove the affected part of the liver when the disease is localized and margins are clear. This offers the best long-term control when it’s caught early and the lesions are resectable.
A transplant may be considered when the liver is badly damaged or the disease can’t be safely removed. It is reserved for carefully selected people and requires close, lifelong specialist follow-up.
Endoscopic procedures place a small tube or stent to open blocked bile ducts and relieve jaundice and itching. This helps prevent infections in the bile ducts and protects remaining liver tissue.
A radiologist uses imaging to guide a thin tube into fluid-filled or infected areas to drain them. This can reduce pain, fever, and sepsis risk while samples are tested to guide care.
Your genes may have an impact on how drugs work for you
The way medicines work for alveolar echinococcosis can vary because genes affect how your liver processes drugs and how parasite targets respond. Pharmacogenetic testing and careful dose monitoring help tailor benzimidazoles to reduce side effects while maintaining effectiveness.
Pharmacological treatments
Medicines for alveolar echinococcosis aim to stop the parasite from growing, often for years and sometimes lifelong. Not everyone responds to the same medication in the same way. Many start treatment when imaging or blood tests suggest active disease, even if early symptoms of alveolar echinococcosis are subtle. Your care team may also combine medicine with procedures or surgery when that’s possible.
Usually the first choice for alveolar echinococcosis and taken long term to keep the parasite from growing. Regular blood tests check liver function and blood counts, and doctors review other medicines for interactions. It’s generally avoided during pregnancy and taken with food to improve absorption.
An alternative if albendazole isn’t tolerated or available, but often needs higher, multiple daily doses. Monitoring is similar—liver enzymes and blood counts are checked regularly. Side effects can overlap with albendazole, including stomach upset and liver irritation.
Sometimes added short term around procedures or when doctors aim for broader parasite coverage, but it’s not a stand‑alone treatment for alveolar echinococcosis. Evidence for benefit is more limited, so it’s used case by case. Your team will explain the goal and planned duration if it’s included.
Genetic influences
Alveolar echinococcosis is caused by a tapeworm parasite picked up from the environment, so it isn’t something you inherit or pass on to your children. It’s natural to ask whether family history plays a role. In practice, families sometimes see more than one case because they share the same exposures, not because of shared genes. That said, differences in how our immune system genes work—like how strongly inflammation switches on—may influence who becomes infected after exposure and how fast the disease progresses. Researchers call this genetic susceptibility to alveolar echinococcosis, but it’s only one factor alongside where you live, outdoor activities, and contact with wild or domestic animals. There’s no routine genetic test to predict risk, and having a particular gene pattern does not mean you will develop alveolar echinococcosis.
Is Alveolar echinococcosis genetic?
Genetics plays a limited role in alveolar echinococcosis, which is an infectious disease, not an inherited one. Variations in immune-system genes may influence risk, severity, and response to infection. Family members don’t inherit the disease, but shared environments can affect exposure.
Pharmacogenetics—how genetics influence drug effects
For Alveolar echinococcosis, treatment often means taking albendazole for months to years, and people don’t all handle this medicine the same way. Genes can influence how quickly you convert albendazole into its active form and how fast you clear it from your system. Differences in liver enzymes and drug transport proteins can shift drug levels up or down, which may change how well the drug works and the chance of side effects; this is why doctors adjust doses, check liver tests, and, in some centers, measure albendazole levels in the blood. Interactions with other medicines and overall liver health can have as much or more impact than genetics, so your team looks at the whole picture when planning Alveolar echinococcosis treatment. Pharmacogenetic testing for Alveolar echinococcosis treatment isn’t routine today, but it may be considered if responses are unexpected or side effects are hard to manage. In those situations, any genetic results are used alongside close clinical monitoring to fine-tune therapy rather than to make one-time yes/no decisions.
Interactions with other conditions
For people already living with liver conditions like hepatitis or cirrhosis, alveolar echinococcosis can add strain: swelling in the belly, jaundice, and fatigue may worsen, and bile-duct blockage can invite bacterial infections of the bile system. Doctors call it a “comorbidity” when two conditions occur together. When the immune system is lowered—after an organ transplant, with long-term steroids, certain biologic medicines, or advanced HIV—alveolar echinococcosis may grow and spread faster, blood tests can be less reliable, and imaging often needs to be repeated more often. Alveolar echinococcosis can resemble liver cancer on scans, so people being evaluated for a tumor, or already in cancer treatment, may need careful imaging and sometimes a biopsy to tell them apart; cancer therapies that suppress immunity can also let the parasite advance more quickly. If someone has gallstones or recurrent cholangitis, the parasite’s cyst-like growths can make blockages and infections more frequent or harder to treat. The main medicine, albendazole, relies on the liver to be processed, so combining it with other liver-stressing drugs can raise the risk of side effects, while some medicines (such as certain anti-seizure drugs) can lower albendazole levels and make it less effective; blood tests to check liver enzymes and drug levels help keep treatment safe. Because early symptoms of alveolar echinococcosis can be subtle and overlap with other illnesses, let your care team know about all diagnoses and medications so they can coordinate testing and tailor treatment.
How genes can cause diseases
Humans have more than 20,000 genes, each carrying out one or a few specific functions in the body. One gene instructs the body to digest lactose from milk, another tells the body how to build strong bones and another prevents the body's cells from beginning to multiply uncontrollably and developing into cancer. As all of these genes combined are the building instructions for our body, a defect in one of these genes can have severe health consequences.
Through decades of genetic research, we know the genetic code of any healthy/functional human gene. We have also identified that in certain positions on a gene, some individuals may have a different genetic letter from the one you have. We call these hotspots "Genetic Variations" or "Variants" in short. In many cases, studies have been able to show that having the genetic letter "G" in the position makes you healthy, but having the letter "A" in the same position disrupts the gene function and causes a disease. Genopedia allows you to view these variants in genes and summarizes all that we know from scientific research, which genetic letters (Genotype) have good or bad consequences on your health or on your traits.
History
Throughout history, people have described long‑lasting belly complaints, unexplained weight loss, and swollen abdomens that slowly worsened over years. In farming regions, some families linked these problems to close contact with foxes or dogs, though the cause wasn’t clear. A worker might feel fine for a long time, then notice fatigue, poor appetite, and a dull ache under the right ribs. By the time a doctor examined them, a firm liver mass and jaundice could be present, pointing to serious liver disease without an obvious trigger.
First described in the medical literature as a peculiar “tumor-like” infection of the liver, alveolar echinococcosis puzzled early clinicians because it behaved like cancer but came from a parasite. In the 1800s and early 1900s, pathologists studying affected livers saw small, branching cysts that invaded nearby tissue. They realized this was different from the more common cystic echinococcosis. Over time, descriptions became more detailed as doctors recognized the condition’s slow course, the risk of spread to lungs or brain, and the link to wildlife cycles involving foxes and small rodents.
From early theories to modern research, the story of alveolar echinococcosis reflects advances in public health and biology. Mid‑20th‑century work mapped areas of risk across parts of Central and Eastern Europe, western China, Japan, and Alaska. Community stories often described the condition appearing in people who gathered wild berries, trapped animals, or kept dogs that roamed and hunted. These observations, along with lab studies, clarified how tiny parasite eggs in the environment could enter the body and settle in the liver, growing slowly over years.
In recent decades, knowledge has built on a long tradition of observation. Imaging such as ultrasound and CT made it possible to spot early symptoms of alveolar echinococcosis before major damage occurred. Blood tests that detect parasite-specific antibodies improved diagnosis, and safer liver surgery techniques, along with long‑term antiparasitic medicines, changed outcomes. What was once frequently fatal can now often be controlled if found early, though treatment usually lasts years.
Advances in genetics helped confirm the identity of the parasite species and track its spread in wildlife and dogs. This clarified why cases rose in some regions as fox populations recovered and urbanized, bringing the parasite closer to towns. Public health campaigns promoted handwashing after outdoor activities and deworming of dogs in high‑risk areas. Not every early description was complete, yet together they built the foundation of today’s knowledge.