The phrase "are difficult to cure" is correct and usable in written English.
It can be used when discussing conditions, diseases, or problems that are challenging to resolve or treat.
Example: "Chronic illnesses such as diabetes and hypertension are difficult to cure, but they can be managed effectively with proper care."
Alternatives: "are hard to treat" or "are challenging to remedy".
Even more problematic, overuse of antibiotics leads to drug-resistant superbugs, which are difficult to cure.
Germs of staphylococcal infections, that are difficult to cure in hospitals, also make at least six infection factors.
Sensory nerve disorders are difficult to cure completely considering poor nerve regeneration capacity and difficulties in accurately targeting neural tissues.
Gene therapy is recognized as a medical approach for the treatment of diseases that are difficult to cure, such as tumors.
Although the prognosis of PNET is better than that of pancreatic cancer [3, 4], some types of PNET, such as those presenting with multiple metastases at the initial diagnosis or with advanced locoregional diseases, are difficult to cure.
Autoimmune disorders in general are difficult to cure.
Workers at the establishment were particularly interested in infections which were difficult to cure.
Chronic hepatitis B virus (HBV) infection is difficult to cure due to the presence of covalently closed circular DNA (cccDNA).
Diabetes mellitus is a common metabolic disease around the world that is accompanied by serious chronic complications and is difficult to cure.
A body of literature has shown the EMT type of CSC plays a critical role in drug resistance and cancer metastasis, which could partially explain why it has traditionally been difficult to cure cancer using cytotoxic chemotherapy.
The basic epidemic models are as follows: SI models (the disease is difficult to cure); ({SIS}) models (the disease can be cured); ({SIR}) models (the disease is cured with lifelong immunity), and ({SIRS}) models (the disease is cured with temporary immunity).
