Perhaps I might provide an answer.
There are many home remedies that tenants and home owners may use to eradicate fleas. A licensed exterminator may be useful.
Your original lease was "legal" even if the landlord signed the lease on a date that did not exist. A mere "scrivener" error that does not affect the substance of the lease, will be ignored in court, and the lease will be enforced. If you have since renewed the lease, the date of signing of the first lease is a historical and irrelevant fact. If you did not renew your lease, your landlord may have the right to terminate your tenancy with a one month notice of termination of tenancy.
Your lease should provide a method for you to place the landlord on notice of a defective condition in the building. Usually, most NY form leases require that any notice that the tenant wishes to be given to the landlord be written and mailed to the landlord by either certified mail or by registered mail. If there is such a "notice" provision in your lease, follow the strict requirements of the lease. Make sure that you have kept good copies of your signed letters to the landlord as well as all receipts from the post office.
You may also contact the code enforcement office in Rochester, New York at:
Read more about your tenant rights at:
In order to assert a breach of the statutory Warranty of Habitability due to the flea infestation in the basement of the building, you would need to establish how a condition outside your apartment affects habitability in your home and whether the lease provides for your right of access to the basement of the building.
The answer provided to you is in the nature of general information. The general proposition being that you should try to avoid a bad outcome if you can.