I want to return two list with the same atribute in WCF

namespace DgsSoapWebService.Models
{
    [DataContract]
    public class Infected
    {
        [DataMember]
        public string Nome { get; set; }

        [DataMember]
        public int Datanasc { get; set; }

        [DataMember]
        public string Cidade { get; set; }

        [DataMember]
        public int Nrutente { get; set; }

        [DataMember]
        public bool Covid { get; set; }

        [DataMember]
        public int ContaminationID { get; set; }
    }
}

public class Isolated : Infected
    {
        [DataMember]
        public bool Internado { get; set; }

        [DataMember]
        public string LocalInternamento { get; set; }

        [DataMember]
        public string DataInternamento { get; set; }
    }

[ServiceContract]
   public interface IInfecteds
   {
       [OperationContract]
       List<Infected> GetNome(string nomefiltro ="");

       [OperationContract]
       Isolated GetAllContaminationID(int contaminationID);
   }

public class Infecteds : IInfecteds
   {
       List<Infected> infecteds;
       List<Isolated> isolateds;


       public Infecteds()
       {
           infecteds = new List<Infected>
           {
               new Infected { Nome = "zeze", Datanasc= 2000-23-12, Cidade="Lisboa", Nrutente= 12344512, Covid = true, ContaminationID = 1}
           };

           isolateds = new List<Isolated>
           {
               new Isolated { Nome = "tone", Datanasc= 2000-23-12, Cidade="Cascais", Nrutente= 23244512, Covid = true, ContaminationID = 1}
           };
       }


       public List<Infected> GetNome(string nomefiltro = "")
       {
           return infecteds.Where(p => p.Nome.Contains(nomefiltro)).ToList();
       }

       public Isolated GetAllContaminationID(int contaminationID)
       {
           return isolateds.FirstOrDefault(p => p.ContaminationID.Equals(contaminationID));
       }

   }