Java Programming

Hello, I have a problem with a query using JBoss.

I have a session bean with this method:

@Stateless
public class VisitBean implements VisitBeanRemote {
	
	@PersistenceContext(unitName="MECSDB") private EntityManager manager;

	public int addHospitalization(Hospitalization hosp) {
		
		Query query = manager.createQuery("from Hospitalization h where h.PatientID=:PID");
		query.setParameter("PID", hosp.getPatient().getSSN());
		if (query.getResultList().size()>0) return -1;
		else {
			manager.persist(hosp);
			return hosp.getId();
		}
	}
}

Where the entity Hospitalization is:

import javax.persistence.*;

@SuppressWarnings("serial")
@Entity
@Table(name="Hospitalization")
public class Hospitalization implements java.io.Serializable {
	
	private int Id;
	private Patient patient;
	private String diagnosis;
	private String therapy;
	
	@Id
	@GeneratedValue
	@Column(name="ID")
	public int getId() {
		return Id;
	}
	public void setId(int id) {
		Id = id;
	}
	
	@OneToOne
	@JoinColumn(name="PatientID")
	public Patient getPatient() {
		return patient;
	}
	public void setPatient(Patient patient) {
		this.patient = patient;
	}
	
	@Column(name="Diagnosis")
	public String getDiagnosis() {
		return diagnosis;
	}
	public void setDiagnosis(String diagnosis) {
		this.diagnosis = diagnosis;
	}
	
	@Column(name="Therapy")
	public String getTherapy() {
		return therapy;
	}
	public void setTherapy(String therapy) {
		this.therapy = therapy;
	}
	
}

And the entity Patient is:

import javax.persistence.*;

@SuppressWarnings("serial")
@Entity
@Table(name="Patient")
public class Patient implements java.io.Serializable {
	
	private long SSN;
	private String name;
	private String surname;
	private int age;
	private String familydoctor;
	
	@Id
	@Column(name="SSN")
	public long getSSN() {
		return SSN;
	}
	public void setSSN(long ssn) {
		this.SSN = ssn;
	}
	
	@Column(name="Name")
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	@Column(name="Surname")
	public String getSurname() {
		return surname;
	}
	public void setSurname(String surname) {
		this.surname = surname;
	}
	
	@Column(name="Age")
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	
	@Column(name="FamilyDoctor")
	public String getFamilydoctor() {
		return familydoctor;
	}
	public void setFamilydoctor(String familydoctor) {
		this.familydoctor = familydoctor;
	}

}

But when I call the method addHospitalization from my program i receive this exception:
org.hibernate.QueryException: could not resolve property: PatientID of: domain.Hospitalization [from domain.Hospitalization h where h.PatientID=:PID]

Can anyone help me to understand how to correct the problem?
Thanks in advance.