message: 'Cast to number failed for value "undefined" at path in nodejs mongoose express

I am getting this error.when i am fetching values from collection, why this error coming. tried many solutions but not working

here is my code please solve this issue

apiRoutes.get('/getdeals/:status/:DealID/:SinceID' , function(req, res, next) {
  var DealStatus = req.status;
  var DealID =req.DealID;
  var SinceID = req.SinceID;

    if(DealStatus==1){
      Adddeal.find({
      $and: [
          { DealID: { $gt: SinceID }},
          { DealStatus: {$eq: 1}}
      ]
  }, function (err, results) {
      if (err) return console.error(err);
      res.json(result);
  });
    }else if(DealStatus==0){
       Adddeal.find({
      $and: [
          { DealID: { $gt: SinceID }},
          { DealStatus: {$eq: 0}}
      ]
  }, function (err, results) {
      if (err) return console.error(err);
      res.json(result);
  });
    }else{
            Adddeal.find({
          DealID: { $gt: SinceID }
  }, function (err, results) {
      if (err) return console.error(err);
      res.json(result);
  });
    }
});

error is :

{ message: 'Cast to number failed for value "undefined" at path "DealID"',
  name: 'CastError',
  kind: 'number',
  value: undefined,
  path: 'DealID',
  reason: undefined }